Imam Sadiq (peace be upon him): It is narrated from Mufaddal ibn Umar: ... Mufaddal said: "My master, what is the ta'wil (interpretation) of لِیُظْهِرَهُ عَلَی الدِّینِ کُلِّهِ وَ لَوْ کَرِهَ المُشْرِکُونَ [That He may make it overcome the religions, all of them, though the polytheists may be averse]? That is, how does the Imam of the age become dominant over all religions?" The Imam (peace be upon him) said: "Its ta'wil is this verse: 'And fight them until there is no fitna [polytheism and the deprivation of freedom], and religion [and worship] is entirely for Allah!' (al-Anfal/39). O Mufaddal, by Allah! He will remove disagreement from among the nations and religions, and all religions will become one." As Allah has said: "Indeed the religion with Allah is Islam [and submission to the truth]." (Al Imran/19). And He has also said: "And whoever chooses for himself a religion other than Islam [and submission to the command of the truth], it will not be accepted from him, and in the Hereafter he will be among the losers." (Al Imran/85). Mufaddal said: "Master! Was the religion that his forefathers Ibrahim, Nuh, Musa, Isa (peace be upon them) and Muhammad (peace be upon him and his family) followed the same religion of Islam?" He said: "Yes, it was the very religion of Islam, none other!" I said: "Do you have proof of this from the Quran?" He said: "Yes; the Quran from beginning to end is full of proofs. Among them is the verse: 'Indeed the religion with Allah is Islam [and submission to the truth].' (Al Imran/19). And also this verse: 'Follow the religion of your father Ibrahim; Allah named you "Muslims" both in earlier scriptures and in this heavenly book.' (al-Hajj/78) — that is, Islam is the religion of your father Ibrahim (peace be upon him), and it is he who named you Muslims. And another is the verse in which Allah, in the story of Ibrahim and Isma'il (peace be upon them), quotes them as saying: 'Make us submissive to Your command! And from our progeny an ummah submissive to Your command.' (al-Baqarah/128) — that is, O Allah, make the two of us two Muslims submitted to You, and bring forth from our descendants also a Muslim people. And another is this verse in the story of Fir'awn, where He says: 'When drowning overtook him, he said: "I believe that there is no deity except the One in whom the Children of Israel have believed, and I am of the Muslims."' (Yunus/90). And in the story of Sulayman (peace be upon him) and Bilqis, the queen of Saba, He says: 'And come to me submissive to the truth!' (al-Naml/31) — come to me. And when Bilqis came to Sulayman (peace be upon him), she said: 'With Sulayman I have submitted (aslamtu) to Allah, the Lord of the worlds!' (al-Naml/44) — that is, I have submitted along with Sulayman (peace be upon him) before the Lord of the worlds. And from the tongue of Isa ibn Maryam (peace be upon him), He says: مَنْ أَنْصارِی إِلَی اللهِ [Who will be my helpers in the way of Allah?] — that is, Isa (peace be upon him) said: 'Who are those who wish to help me by accepting the religion of Allah?' The disciples [his special students] said: 'We are the helpers of Allah; we have believed in Allah, and bear witness [you also] that we have submitted (are Muslims).' (Al Imran/52). And in another verse He says: 'And all those in the heavens and the earth submit to [the command of] Him, willingly or unwillingly.' (Al Imran/83). And in the story of Lut (peace be upon him) He says: 'But we did not find in them, except one household of the believers!' (al-Dhariyat/36). And in another verse He says: 'Say: "We have believed in Allah and in what has been sent down to us, and in what was sent down to Ibrahim, Isma'il, Ishaq, Ya'qub and the prophets from among his descendants, and [likewise] in what was given to Musa and Isa and the [other] prophets from their Lord, and we make no distinction between any of them, and we are submissive to the command of Allah [and racial prejudices and personal motives do not cause us to accept some and abandon others]."' (al-Baqarah/136)."