Hazrat Mahdi's (as) weapons are faith and love

Hazrat Mahdi (as) and his followers will defeat the irreligious mindset, meaning its system of ideas, with the Qur’an, science, reason, knowledge and faith. Victory will arise in belief and ideas and, insha’Allah, superstitious thinking, perversion and Darwinist, materialist and atheist thinking will all vanish.

Narrated from Hazrat Amr ibn Awf (ra):

The Day of Judgment will not come until Constantinople of the Rome is captured by Muslims with tasbih (praising of Allah) and takbir (proclamation of the greatness of Allah). (Ramuz al-Ahadith, p. 478)

In a hadith narrated by Imam Muslim from Abu Hurairah, our Prophet (saas) one day addressed the companions thus:

“… When these strugglers come and settle in that land they will not wage war with weapons, and they will not fire arrows. They will recite the takbir by saying La ilaha illallahu akbar.

At this takbir, one of the ramparts on either side of the city will fall. Then they will recite a second takbir. Subsequently, the other side of the city will fall. They will then recite a third takbir. At this, breaches will open up in the ramparts and the army of Islam will enter and capture the city. (Ash-Sharani, Mukhtasar Tazkirah al-Qurtubi, p. 445-446)

Muslims will not fight when they come to this city. The sea side of the city will fall when they recite the takbir, and the other side will fall when they recite the takbir again, when they recite the takbir for the 3rd time, the whole city will be captured. (Ibn Hajar al-Haythami, Al-Qawl al-Mukhtasar fi `Alamat al-Mahdi al-Muntadhar, p.30)

Hazrat Mahdi (as) and his followers will capture Istanbul and a great many cities of the world by remembering Allah in a moral, intellectual and cultural way, and morally eradicate Darwinism and materialism. In this verse of the Qur’an, Almighty Allah points out intellectual eradication:

Rather We hurl the truth against falsehood and it cuts right through it and it vanishes clean away! (Surat al-Anbiya’, 18)