Every astute and heedful person can explicitly see that the system of the Mahdi is referred to in the entire Qur'an.
In the Qur'an, God heralds that Islamic morality will prevail in the world. When Islamic morality prevails in the world, the spiritual leader and pioneer of Muslims will be Hazrat Mahdi (pbuh). It has been stated in the hadiths that Islamic morality will prevail in the whole world by means of Hazrat Mahdi (pbuh), in this century: For that reason, every verse mentioning the prevalence of Islamic morality is about the system of the Mahdi.
"God has promised those of you who have faith and do right actions that: He will make them successors in the land as He made those before them successors, and will firmly establish for them their religion with which He is pleased and give them, in place of their fear, security..." (Surat An-Nur, 55)
"Then We appointed you after them to be khalifs on the earth." (Surah Yunus, 13-14)
Our Lord has made a promise to Muslims and God, in many verses of the Qur'an, declares that “God never breaks His promise” .Then the promise of God in this verse will come true as well provided that they sincerely adopt the morality of a believer; God will make them successors in the land. Islamic morality will prevail in the entire world, and these days full of fear will end; instead, there will be days of trust, peace, and joy. Wars, massacres, terrorism and anarchy will cease; the oppressed people whose rights are being encroached upon and who are abused will lead to salvation.
While giving this promise, God states “...as He made those before them successors.” And, God declares that these people who were successors in the land before us are the Prophet Solomon (pbuh) and Hazrat Dhu'l-Qar'nayn (pbuh). Our Prophet (saas), in regard to the promise in the Qur'an, announces that (saas) Hazrat Mahdi (pbuh) is the third person that will make Islamic morality prevail in the world just like the Prophet Solomon (pbuh) and Hazrat Dhu'l-Qarnayn (pbuh):
"HAZRAT MAHDI (AS) WILL (SPIRITUALLY) RULE THE WORLD just like the Prophet Solomon (pbuh) and Dhu’l-Qarnayn (pbuh). "(Al-Barzanji, Al-Isha'ah li-ashrat al-sa'ah, p. 29)
There are four rulers on Earth in total. Two are from the believers and two from the unbelievers. The believers are Solomon (pbuh) and Dhu’l-Qarnayn (pbuh). The unbelievers are Nimrod and Nebuchadnezzar. ONE FROM MY PEOPLE WILL RULE THE WORLD AS THE FIFTH. In other words, THE MAHDI. (Imam Rabbani, Letters of Rabbani, 2/251)
Insha’Allah, our Lord has promised this, and it will happen exactly as He promised: With the will of God, Hazrat Mahdi (pbuh), will establish Islamic morality all over the world, and all believers will gather around; the world will literally adopt an understanding of brotherhood, peace and security.
We wrote down in the Zabur, after the Reminder came: "It is My servants who are righteous who will inherit the earth." (Surat Al-Anbiya', 105)
The Qur'an is the True Book that communicates the words of God which are precise and will never change. And God promised: “He will make Muslims, who have faith, successors in the world and Islamic morality will prevail all over the world.” This promise of God is mentioned in the True Books prior to the Qur'an as well, and it is a definite promise.
When God's help and victory have arrived, and you have seen people entering God's religion in droves, then glorify your Lord’s praise and ask His forgiveness. He is the Ever-Returning. (Surat An-Nasr, 1-3)
God promised to grant "help” and “a victory.” from His Own Presence to the believers. That victory is the prevalence of Islamic morality throughout the world. In this way, the help and victory of God will certainly come true. There will be a spiritual victory and people will head towards faith. Our Lord declared that as a result of the help and the victory, people in the world will embrace Islam as the true religion in droves, in other words, in very large masses and Islamic morality will prevail all over the world.
"And other things that you love: support from God and imminent victory. Give good news to the believers." (Surat As-Saff, 13)
Our Lord heralds a great blessing about which Muslims will be very glad: "The support, victory and an imminent breakthrough," from the Sight of God. This victory is a spiritual victory. The promise of God will come true and the world will find the True Path by the help of God, which Muslims have longed for. God promised to grant His support to Muslims around the world who are oppressed, persecuted, downtrodden, and are prevented from practising their religion. God declared that He will grant them a victory and a conquest, in other words, will “make them prevail” Islamic morality will prevail all over the world; and Muslims will be victorious by the help of God.
"Our Word was given before to Our servants, the Messengers: That they would certainly be helped. And [that] indeed; It is Our army which will be victorious.” (Surat As-Saffat, 171-173)
The End Times is the period when the world deteriorates in the most severe way. In these years, people will be morally more corrupt than ever before; wars and chaos in the world, and massacres and murders will seem more violent than ever before. Many people under these circumstances will have given up hope for the rule of peace, love, affection and tolerance on the earth. However, God promised. He gave a promise to His servants. He declared, “Certainly, you will find nusrat [the help of God].” “The help of God will, certainly, come, and good morality, love, peace will absolutely prevail the world.” Since God promised for His servants on the True Path to grant “victory.” And, God said “… indeed, it is Our army which will be victorious” and, thus, declared that there is no doubt in the truthfulness of His Promise. This victory and glory is certain. God promised that the party who will prevail in the end will not be those who are unbelievers, but, insha’Allah, the followers of God.
"God has written: ‘I will be victorious, I and My Messengers.' Indeed, God is Most Strong, Almighty." (Surat Al-Mujadilah, 21)
There is no strength and power other than God: God is One Who rules all the happenings, all the people in the world. God said, “I will be victorious.” There is no power that can change the Word of God. God declared that His Messengers will be instrumental in this victory and this prevalence. In the End Times we live in now, God revealed His Name "Al-Hadi" and designated Hazrat Mahdi (pbuh) as "Hatem al-wali" (the last friend of God) by assigning him to lead people to the true path." Hazrat Mahdi (pbuh), as the envoy of God, will be intellectually victorious against all atheistic ideologies and systems, and Islam, the morality in the Qur'an, love and peace will prevail in the world.
"Do not imagine that God will break His promise to His Messengers. God is Almighty, Exactor of Revenge." (Surah Ibrahim, 47)
Some people give way to despair due to the deterioration of the incessant dissension going on in the world. Even though they say they believe in God and in the Qur'an, they forget about the Promises of God and believe that there will be no salvation. See that our Lord warns people who become ignorant. God declared that He never breaks His promise by saying that “Do not imagine that God will break His promise to His Messengers.” Islamic morality will prevail and intellectually dominate the entire world. The deterioration in the world will cease, and the earth will be a land of beauty in which people act perfectly in accordance with the morality in the Qur'an and the Messengers of God will be instrumental in this.
"It is He Who sent His Messenger with guidance and the Religion of Truth to exalt it over every other religion, though the idolaters hate it." (Surat As-Saff, 9)
"It is He Who sent His Messenger with the Guidance and the Religion of Truth to exalt it over every other Religion. And God suffices as a witness." (Surat Al-Fath, 28)
God promised that the superstitions and deviant beliefs prevailing in the world will be completely eliminated, no matter how widely they are accepted. The former true religions which are being distorted and altered; the perverted ideologies such as Darwinism, materialism, atheism; all of the superstitious ideologies based on changing the religion and attributing partners to God, including bigoted ideas and superstitions will be eliminated. The real Islamic morality will prevail against all of these perverted ideologies. In the end, what prevails in the world will be the morality in the Qur'an and the sincere faith.
"It is He who sent His Messenger with guidance and the Religion of Truth to exalt it over every other religion, even though the idolaters detest it." (Surat At-Tawba, 33)
One of the greatest obstacles to the prevalence of the real Islamic morality in the world is “bigotry”. A bigoted understanding, which attempts to manipulate the original form of the religion, as described in the Qur'an and notified by our Prophet (saas), and to adopt it to their own distorted beliefs, is in a very serious struggle against the preaching and the adoption of the morality in the Qur'an as well as its prevalence in the world. However, God declared that this uphill struggle will end up with the victory and prevalence of the true morality in the Qur'an. The promise of God will be fulfilled, despite the resistance of all of the perverted beliefs attributing partners to God with all their strength, and Islamic morality will achieve to spiritually prevail in spite of all of the deviant beliefs, ideologies and ideas.
"We will leave you the land to live in after them. That is (the reward) of those who fear My station and fear My threat. They asked for God's victory, and [therefore] every obdurate tyrant failed." (Surah Ibrahim, 14-15)
God says, "We will leave you the land to live in" in other words, He says that He will leave Muslims the world to live in. God declared that it is a blessing, a benediction, and good news from His Presence for His servants who fear His station and His threat. Today, the believers from all over the world seek the Help of God and pray Him to protect and save them from the difficulties and troubles they are faced with. They pray to God to cease the dominance of the persecutors. Our Lord promises and gives the good news that this spiritual victory people are praying for will certainly be attained and that the dominion and the oppression of the persecutors will certainly come to an end. Eventually, Islamic morality will certainly become victorious and will certainly prevail in the world.
"Then We will rescue Our Messengers and those who have faith as well. It is incumbent upon Us to rescue the Muslims." (Surah Yunus, 103)
God specifically created the struggles, difficulties, chaos and conflicts in the world in order to test the people. God certainly promised a salvation to His servants who have the sincere faith for Himself when they encounter such struggles. This is a definite Custom of God. All Messengers and all Muslims have been tested by these struggles throughout the history and, in the end, they have always been granted with the help of God in return. The Custom of God will manifest itself in the same way in the End Times as well. God will certainly lead His messengers and true believers to the salvation and will make them successors. Our Lord declared that this is a definite and true promise.
"... He knew what you did not know and ordained, in place of this, an imminent victory (grant)." (Surat Al-Fath, 27)
"... The unbelievers will soon know who has the Ultimate Abode." (Surat Ar-Ra‘d, 42)
"Say: ‘Everyone is waiting expectantly, so wait expectantly. You will soon know who are the Companions of the Right Path and who is guided.'" (Surat Ta Ha, 135)
God reminds us a very important fact in the verses: “God is the One Who knows what people do not.” Some people who do not think about this fact judge the world, the events, the people and what will potentially happen in the future merely by the things that they can see, hear or know and when they consider the current situation of the world, many people believe that it is impossible to recover from such a corruption and deterioration. However, it is a mystery of the test created by God. God is the One Who knows what people do not. The only One Who knows what will happen in the future is our Lord and God has declared that there will not be corruption and deterioration, instead, there will be an environment full of beauty, peace, happiness, joy, and wealth, like the Golden age, will prevail by the end of the world. God promised that this world will end with the victory and spiritual dominance of the believers, and the prevalence of Islamic morality. God also reminds us that the people who do not believe in this fact or regard it as possible, will witness this beautiful end as well.
"Except those who have faith and do right actions and remember God repeatedly and defend themselves after they have been wronged? Those who do wrong will soon know the kind of reversal they will receive!" (Surat Ash-Shu‘ara’, 227)
People should not be deluded by the dominion of oppression and persecutors in the world or by the fact that this dominance is strong enough to appear unshakable. Our Lord informs us that this reign of oppression "is created to be overthrown." Those who do wrong will certainly face the punishment of God and those who have sincere faith will certainly prevail over them: God promised that on the condition that “they have the sincere faith, do right actions and remember God repeatedly”, He will certainly grant “a definite victory” to Muslims after this persecution and God declared in the verse that this victory “is imminent.”
"Rather We hurl the truth against falsehood and it cuts right through it and it vanishes clean away! Woe without end for you for what you portray!" (Surat Al-Anbiya', 18)
"God confirms the Truth by His Words, even though the evildoers hate it." (Surah Yunus, 82)
God created all contrasts together as a requirement of the test in this worldly life. Our Lord wants people to see the right choices and assume an attitude alongside the truth. For that reason, there are also a great number of distorted beliefs, thoughts and ideologies in the world, along with the true religion; furthermore, God stated that the majority of people will take sides with these distorted beliefs. However, the Truth would eventually be victorious. God promised that the right ideology, in other words, the morality of the Qur'an, will certainly prevail against all these distorted ideas. Even though these ideas are prevalent now, that will not change the result God ordained. Falsehood is bound to vanish. The Truth will always be victorious.
"They desire to extinguish God's Light with their mouths. But God refuses to do other than perfect His Light, even though the unbelievers detest it." (Surat At-Taubah, 32)
" They desire to extinguish God's Light with their mouths but God will perfect His Light, though the unbelievers hate it." (Surat As-Saff, 8)
Our Lord imparted to us critical information in the Qur'an: Some people will struggle to cover up what is right. To this end, they will utilize every means available such as written, visual means, and will broadcast in order to destroy what is right. However, according to the verses, this will not be possible because God promised His servants that He will perfect His Light. This will be only possible when God makes Islamic morality prevail in the entire world, insha’Allah. The word “perfect” that God used in the relevant verse is critical. Since our Lord promised that not a certain majority of people but all of them will find the true path as a result of the fulfilment of this announcement and thus His Light will be perfected.
"He bequeathed their land, their houses and their wealth to you, and another land you had not yet trodden on. God has power over all things." (Surat Al-Ahzab, 27)
"And We bequeathed to the people who had been oppressed the easternmost part of the land We had blessed, and its westernmost part as well..." (Surah Al-A‘raf, 137)
" God will give security those who had taqwa(piety) in their victorious Safe Haven. No evil will touch them and they will know no sorrow." (Surah Az-Zumar, 61)
There is a small group of true believers, but a large group of unbelievers in the world. This is a Custom of God that God reported in the Qur'an. For that reason, today, many people of sincere faith in various parts of the world encounter the pressure, oppression, and persecution of the unbelievers. Many of them are exiled from their homeland; their properties are confiscated; they are deprived of their civil and legal rights of any nature; they are captured and martyred. However, our Lord promised that the pain and suffering that these oppressed people experience will certainly come to an end. At the end of all these troubles and sufferings, God imparted to us that He will make sincere Muslims who genuinely believe successors to the four corners of the world. By saying, "We bequeathed to the people who had been oppressed the easternmost part of the land We had blessed, and its westernmost part as well…" God states that this spiritual dominion of those who believe will encompass the whole of the world.