Prophet Muhammad (pbuh) had said:
“You surely would follow the path of those (who lived) before you, yard by yard step by step; to the extent that even if they enter into a hole of a lizard you would enter, too.”
We said: The Jews and the Christians?
Who else?, he said.” (Imaam Bukhaari, al-I’tisam bi’l-Kitab wa’l-Sunnah, 14)
Shirk (associating partners with God) is the most disastrous sin in Christianity. “The first commandment forbids joining others. It obliges to believe in no other gods than the God, and to worship Him only.” Jesus (pbuh) said: “Worship the Lord your God and serve him only.” (Luke 4:5-8; New International Version)
Jesus (pbuh) was considered as human in the Apostolic Age. Moreover, none of the Gospels mentions divinity of Jesus. Paul opened the way for this. Paul, who is believed to be born in 10 AD, could not happen to see Jesus although he was contemporary with him; because he was living in Tarsus. While he was a deadly enemy of Christianity, he declared his conversion to Christianity a little while after the death of Jesus. Although the Apostles were alive and they tried to deter him, he managed to convince people that, as he neared Damascus on his journey, suddenly a light from heaven flashed around him, heard a voice from Jesus, and was baptized. He also managed to put his words into the Bible presenting himself as the representative of Jesus. Considerable part of the New Testament consists of Letters of Paul.
Paul accepted the existence of gods apart from the God and assumed Jesus as their only Lord among them. His statements in the Bible are as follows:
“For though there are things that are called “gods,” whether in the heavens or on earth; as there are many “gods” and many “lords”; yet to us there is one God, the Father, of whom are all things, and we live for him; and one Lord, Jesus Christ, through whom are all things, and we live through him.”
Paul used the word “lord” masterfully. Lord means owner. Arabs used to call the owner of a slave as ‘lord’. Joseph had been sold as slave to an Egyptian official; the official’s wife had fallen in love with him and wanted to be with him. Relevant verse of Qur’an is as follows:
“And it so happened that the lady in whose house Joseph was living, sought to tempt him to herself, and one day bolting the doors she said:
“Come on now!” Joseph answered: “May God grant me refuge! Indeed, your husband is my Lord (إِنَّهُ رَبِّي). He has provided an honorable abode for me. Wrongdoers never prosper.”” (Josef 12:23)
The word ‘lord’ is mostly used for God. Those who refuse to be servants of anyone other than God refuse to call anyone else ‘my lord’. The relationship between the slave and the owner is involuntary. A slave wants to be free as soon as possible. The relationship between the man and God is voluntary. Those who seek to wrong people choose equivocal words to defend themselves easily. If a Christian assumes Jesus as the Lord, he/she would easily ascribe divinity to Jesus, thereby turning the relationship into a voluntary form. This attitude of Paul had been the first step to deify Jesus.
Paul said, assuming himself as the slave and envoy of Jesus Christ:
“Paul, a servant of Jesus Christ, called to be an apostle, set apart for the Good News of God, which he promised before through his prophets in the holy Scriptures, concerning his Son, who was born of the seed of David according to the flesh, who was declared to be the Son of God with power, according to the Spirit of holiness, by the resurrection from the dead, Jesus Christ our Lord, through whom we received grace and apostleship, for obedience of faith among all the nations, for his name’s sake.” “Whatever you do, in word or in deed, do all in the name of the Lord Jesus, giving thanks to God the Father, through him.”
Paul, going further, misrepresented the Jesus falsely equating him with God by his words: “Christ Jesus, who, existing in the form of God, didn’t consider equality with God a thing to be grasped.”
Pauline Christians decided at First Council of Nicaea in 325 that Jesus was not created, he is Son of God, and he existed from eternity along with God the Father. Divinity of Jesus was announced at Council of Chalcedon that was held in 451:
“We, then, following the holy Fathers, all with one consent, teach people to confess one and the same Son, our Lord Jesus Christ, the same perfect in Godhead and also perfect in manhood; truly God and truly man, of a reasonable [rational] soul and body; con-substantial [co-essential] with the Father according to the Godhead, and con-substantial with us according to the Manhood; in all things like unto us, without sin; begotten before all ages of the Father according to the Godhead, and in these latter days, for us and for our salvation, born of the Virgin Mary, the Mother of God…”
Since today’s Christians internalized polytheism, they do not admit the pre-Paul Christianity. God ordains in the Qur’an:
لَقَدْ كَفَرَ الَّذِينَ قَالُوا إِنَّ ا هل هََل هُوَ الْمَسِيحُ ابْنُ مَرْيَمَ وَقَالَ الْمَسِيحُ يَا بَنِي إِسْرَائِيلَ اعْبُدُوا ا هل هََل رَبِّي وَرَبَّكُمْ إِنَّهُ مَنْ يُشْرِكْ بِا هل هَِل فَقَدْ حَرَّمَ ا هل هَل عَلَيْهِ الْجَنَّةَ وَمَأْوَاهُ النَّارُ وَمَا لِلظَّالِمِينَ مِنْ أَنْصَارٍ.
“And surely they denied the truth when they said: ‘Christ, the son of Mary, is indeed God’; whereas Christ had said: ‘Children of Israel! Serve the God, Who is your Lord and my Lord.’ Indeed the God has forbidden the Gardens to those who join others with Him, and their refuge shall be the Fire. No one will be able to help such wrong-doers.” (Al-Ma’ida/The Feast 5:72)
 Catechism of the Catholic Church, Cardinal Joseph Ratzinger,1994.
This work is the product of a 12-bishops commission headed by Cardinal Joseph Ratzinger (former Pope), took 6 years, promulgated by Pope John Paul II. Includes the doctrines accepted by the Church. Cardinal Joseph Ratzinger was the former Pope of the Catholic Church.
 Catechism of the Catholic Church, par. 465.
 Gunduz, Sinasi; Pavlus Hıristiyanligin Mimari, Ankara 2004, p. 32.
 Bible/ The Acts of the Apostles 9: 3-6
 Bible/ The Acts of the Apostles 9: 18 and the rest
 Paul’s Letter to the Colossians 3:17.
 Paul’s Letter to the Philippians 2:6.
 Catechism of the Catholic Church, par. 465.
 Catechism of the Catholic Church, par. 467.