Steadfastness is the determination to make every effort necessary to achieve a certain goal, without any regard for the difficulties that might result along the way. Essentially, steadfastness is an important moral quality that a believer must possess to win Allah's favor. In the following verse, Allah warns believers that they must show determination in performing acts of worship:
He is Lord of the heavens and the earth and everything in between them, so worship Him and persevere in His worship. Do you know of any other with His Name? (Surah Maryam, 65)
In the Qur'an, Allah says that He has ordained all the commands and prohibitions, that sincere and devout believers must follow, and has revealed the faith and moral qualities according to which they must live in this world. Every believer knows he is responsible to Allah, and that he must win His approval. Therefore, he complies with every prescription and prohibition that Allah has revealed, in the attempt to attain the kind of moral perfection that will make him worthy of Paradise. Believers serve Allah as best as they can; their every thought and action is to win His favor.
In many verses of the Qur'an, Allah explains the kind of worship that believers must perform. Believers show no laxity in performing their acts of worship, and fulfill them with determination and willingly. In the Qur'an, Allah tells us about this determination:
(They are men) not distracted by trade or commerce from the remembrance of Allah and the establishment of prayers and the payment of alms; fearing a day when all hearts and eyes will be in turmoil. (Surat an-Nur, 37)
As Allah says in verse 37 of Surat al-Hajj, "Their flesh and blood does not reach Allah but your heedfulness does reach Him. In this way He has subjected them to you so that you might proclaim Allah's greatness for the way that He has guided you. Give good news to the good-doers.", believers know that what will make their acts of worship worthy in the sight of Allah are the intentions in their heart. For this reason, they are very careful to act with true sincerity.
Believers show this steadfastness in their worship in order to attain the high moral character that pleases Allah, and which He has described in the Qur'an. The struggle with their lower-selves to attain moral excellence also reveals their sense of determination in this regard.
In the test that is this earthly life, Allah has revealed two paths to human beings: the good and the evil. In order to retain good moral character throughout their lives, they must be careful not be diverted into the evil ways of their lower-selves. For example, in a situation that might incite anger, a believer restrains himself, and acts in a conciliatory fashion. When he meets an arrogant individual, he does not return arrogance for arrogance, but maintains a modest composure. In the Qur'an, our Lord says: "… People are prone to selfish greed..." (Surat an-Nisa', 128). He commands us to be cautious against the selfishness of our lower-selves, and to be steadfast in exhibiting good morals. One who pursues the kind of morality revealed by Allah is generous, and thinks of others before himself. He is composed under all situations and always speaks best of other people.
Believers feel a great sense of respect for the moral teachings of the Qur'an. Whether their lives are trying, filled with much anxiety, or prosperous and comfortable, they never compromise the moral teachings of the Qur'an. As Allah says in the Qur'an, "Those who, when disaster strikes them, say, 'We belong to Allah and to Him we will return,'" (Surat al-Baqara, 156), they never lose their sense of devotion and submission to Him. This way of practicing their faith gives believers strength of character, and, ultimately enhances their faith. In the Qur'an, Allah praises this superior moral character to be found in believers, as well as their faithfulness and submission to Him:
Who could have a better religion than someone who submits himself completely to Allah and is a good-doer, and follows the religion of Ibrahim, a man of pure natural belief? Allah took Ibrahim as an intimate friend. (Surat an-Nisa', 125)
In the Qur'an, Allah praises the Prophet Ibrahim (as) for his submission to the religion, and reveals that He had made him His friend. He tells us that believers are those who are devoted to Him, and whose submission does not falter under any circumstance:
(Believers are) those who, if We establish them firmly on the earth, will perform prayer and give the alms, and command what is right and forbid what is wrong. The end result of all affairs is with Allah. (Surat al-Hajj, 41)
Another characteristic of the believers, which shows forth their steadfastness in complying to the moral teachings of the Qur'an, is the effort they expend to win Allah's favor. They continually think of pleasing Him, performing good works to this end. They sincerely desire to be a servant whom Allah loves, and upon whom He showers His mercy. Throughout their lives, they make Allah their guardian, and worship Him, making the morality of the religion sincerely His. Believers are never lax in their efforts to strengthen their faith, demonstrating that their faithfulness to Allah has achieved for them true firmness.