"And We sent not before you any messenger except that We revealed to him that, "There is no deity except Me, so worship Me."

(Qur'an:21:25) All Prophets taught "God is ONE" Moses (as) Exodus 20:3 (ESV) “You shall have no other gods before me. Deuteronomy 5:7 (ESV) “‘You shall have no other gods before me. Deuteronomy 6:4-10 (ESV) “Hear, O Israel: The Lord our God, the Lord is one. 5You shall love the Lord your God with all your heart and with all your soul and with all your might. 6And these words that I command you today shall be on your heart. 7You shall teach them diligently to your children, and shall talk of them when you sit in your house, and when you walk by the way, and when you lie down, and when you rise. 8You shall bind them as a sign on your hand, and they shall be as frontlets between your eyes. 9You shall write them on the doorposts of your house and on your gates. Deuteronomy 6:14 (ESV) You shall not go after other gods, the gods of the peoples who are around you— David (as) Psalm 77:13 (ESV) Your way, O God, is holy. What god is great like our God? 2 Samuel 22:32 (ESV) “For who is God, but the Lord? And who is a rock, except our God? Job (as) Job 5:8 (ESV) “As for me, I would seek God, and to God would I commit my cause, Job 34:23 (ESV) For God has no need to consider a man further, that he should go before God in judgment. Job 35:2 (ESV) “Do you think this to be just? Do you say, ‘It is my right before God,’ Isaiah (as) Isaiah:45:5-7 (ESV) " I am the Lord, and there is no other, besides me there is no God; I equip you, though you do not know me,6 that people may know, from the rising of the sun and from the west, that there is none besides me; I am the Lord, and there is no other. 7I form light and create darkness, I make well-being and create calamity, I am the Lord, who does all these things. Isaiah:46:5 “To whom will you liken me and make me equal, and compare me, that we may be alike? 6 Those who lavish gold from the purse, and weigh out silver in the scales, hire a goldsmith, and he makes it into a god; then they fall down and worship! 7 They lift it to their shoulders, they carry it, they set it in its place, and it stands there; it cannot move from its place. If one cries to it, it does not answer or save him from his trouble. 8“Remember this and stand firm, recall it to mind, you transgressors, 9remember the former things of old; for I am God, and there is no other; I am God, and there is none like me, Isaiah 46:9 (ESV) remember the former things of old; for I am God, and there is no other; I am God, and there is none like me, Isaiah 45:22 (ESV) “Turn to me and be saved, all the ends of the earth! For I am God, and there is no other. Hosea (as) Hosea 11:9 (ESV) I will not execute my burning anger; I will not again destroy Ephraim; for I am God and not a man, the Holy One in your midst, and I will not come in wrath. Jeremiah (as) Jeremiah 16:20 (ESV) Can man make for himself gods? Such are not gods!” Malachi 9(a.s) Malachi:2:10 (ESV) "Have we not all one Father? Has not one God created us? Why then are we faithless to one another, profaning the covenant of our fathers Jesus Christ (a.s) Mark:12:29 "Jesus answered, “The most important is, ‘Hear, O Israel: The Lord our God, the Lord is one" Quran:19:36 [Jesus said], "And indeed, Allah is my Lord and your Lord, so worship Him. That is a straight path." John:20:17"Jesus said to her, “Do not cling to me, for I have not yet ascended to the Father; but go to my brothers and say to them, ‘I am ascending to my Father and your Father, to my God and your God.’” Muhammad (s.a.w) Qur'an:112:1-4بِسۡمِ ٱللهِ ٱلرَّحۡمَـٰنِ ٱلرَّحِيمِ قُلۡ هُوَ ٱللَّهُ أَحَدٌ (١) ٱللَّهُ ٱلصَّمَدُ (٢) لَمۡ يَلِدۡ وَلَمۡ يُولَدۡ (٣) وَلَمۡ يَكُن لَّهُ ۥ ڪُفُوًا أَحَدٌ (٤) In the name of Allah, the Beneficent, the Merciful Say: He is Allah, the One! (1) Allah, the eternally Besought of all! (2) He begetteth not nor was begotten. (3) And there is none comparable unto Him. (4) Qur'an:16:2 Pickthall He sendeth down the angels with the Spirit of His command unto whom He will of His bondmen, (saying): Warn mankind that there is no Allah save Me, so keep your duty unto Me. Qur'an:3:18 Pickthall Allah (Himself) is Witness that there is no Allah save Him. And the angels and the men of learning (too are witness). Maintaining His creation in justice, there is no Allah save Him the Almighty, the Wise