Almighty Allah had been sending Prophets and Messengers to mankind in order to invite them to the worship of Allah alone, to order them not to worship anything else besides Allah and bring them out of the darkness of polytheism and into the light of Monotheism. All the Prophets preached the belief in the Oneness of Allah therefore we come across with numerous verses in Quran and Bible that authenticates the core belief of Islam, Christianity and Judaism which is oneness of Allah.  The following verses from the Noble Qur’an prove this fact:

وَلَقَدْ بَعَثْنَا فِي كُلِّ أُمَّةٍ رَّسُولًا أَنِ اعْبُدُوا اللَّهَ وَاجْتَنِبُوا الطَّاغُوتَ ۖ

{And verily We have sent among every nation a Messenger (proclaiming) worship Allah alone and avoid Taaghoot (false deities)}, 16:36

قُلْ يَا أَهْلَ الْكِتَابِ تَعَالَوْا إِلَىٰ كَلِمَةٍ سَوَاءٍ بَيْنَنَا وَبَيْنَكُمْ أَلَّا نَعْبُدَ إِلَّا اللَّهَ وَلَا نُشْرِكَ بِهِ شَيْئًا وَلَا يَتَّخِذَ بَعْضُنَا بَعْضًا أَرْبَابًا مِّن دُونِ اللَّهِ ۚ فَإِن تَوَلَّوْا فَقُولُوا اشْهَدُوا بِأَنَّا مُسْلِمُونَ

Say, “O People of the Scripture, come to a word that is equitable between us and you – that we will not worship except Allah and not associate anything with Him and not take one another as lords instead of Allah.” But if they turn away, then say, “Bear witness that we are Muslims [submitting to Him].”  (3:64)

  Since Bible is the manipulated and altered form of Tawrat and Injil, still we find some concrete and solid evidences that illustrate that those who believe in Bible must also believe in one and only God. And on the basis of these similar commandments, Allah invites Christians and Jews to come to an equitable belief. Monotheism is explicitly mentioned in the Bible with the following words: According to the Bible it was taught by Moses: Hear, O Israel: The Lord our God, the Lord is one. (Deuteronomy 6:4) According to the Bible it was taught by Jesus that the most important commandment of God is believing in one Lord: One of the teachers of the law came and heard them debating. Noticing that Jesus had given them a good answer, he asked him, “Of all the commandments, which is the most important?” The most important one,” answered Jesus, is this: “Hear, O Israel: The Lord our God, the Lord is one.” (Mark 12:28-29) Read some more verses on Monotheism in Bible:

• You shall have no other gods before me. You shall not make for yourself an image in the form of anything in heaven above or on the earth beneath or in the waters below. (Deuteronomy 5:7-8)
• Fear the Lord your God, serve him only and take your oaths in his name. Do not follow other gods, the gods of the peoples around you. (Deuteronomy 6:13-14)
• “.There is one God, and there is no other but He” (Mark 12:32)
• Jesus said to him,“Away from me, Satan! For it is written: “Worship the Lord your God, and serve him only.” (Matthew 4:10)
• “I am the Lord your God who brought you out of the Egypt. You shall acknowledge no God but me, no savior except me “(Hosea 13:4)
• “I am the Lord your God that brought you out of the land of Egypt, out of the home of bondage, thou shall have no other God besides Me, thou shall not make any graven image of the heaven above, beneath or in the water under the earth. Thou shall not bow down to them or serve them.” (Exodus 20:2-5)
• “O come, let us bow down and worship, let us kneel before the Lord, our maker. For we are the people of His pasture and the sheep of His voice and He is our God” (Psalms 95:6-7)

Not only has this but the Bible also urged its followers to worship like Muslims:

• “And he (Jesus) went a little further and fell on his face, and prayed.” (Matthew 26:39)
• “And Joshua fell on his face to the earth and did worship.” (Joshua 5:14)
• “And he (Elijah) cast down himself upon the earth and put his face between his knees” (Kings 18:42)
• “And they (Moses and Aaron) fall upon their faces.” (Numbers 20:6)
• “And Abraham fell on his face.” (Genesis 17:3)

  From this conversation, you will observe that worshiping other than one Lord is not only against the teachings of Islam but simultaneously it is against the teachings and commandments of Bible. The one who believes in the Bible must also believe in the oneness of God.