The moment we begin to speak with a Muslim, typically he or she will get offended by the fact that we are calling Jesus the Son of God. This is because when we say "Son of God", they think we are talking about a son who was conceived in the traditional, "normal" way, and they believe this assertion is blasphemy. They are right to believe this assertion is blasphemy. We must clarify to the Muslim that when we say, "Son of God', we do not believe that God ever had a physical relationship with a woman to have this son.
As we look at the Quran and what the Holy book says about Isa Al-Masih (Jesus the Messiah), we see in chapter 19th the angel talking to Maryam (Mary):
Quran 19:19 He said: "Nay, I am only a messenger from thy Lord, (to announce) to thee the gift of a holy son.
Here Isa (Jesus) is referred to as a Holy Son, but please take note what is says in chapter 112:
Quran 112:1 Say: He is Allah, the One and Only;
Quran 112:2 Allah, the Eternal, Absolute;
Quran 112:3 He begetteth not, nor is He begotten; (or, God neither gave birth nor is born)
Here we read that Allah begetteth no one.
Islam fights the major doctrine in Christianity. First, the doctrine of devils and seducing spirits had found its way into the church through the teachings of the trinity. And we know that there was many form of trinity in early church history. This condemned teaching is taught by the Churches and Quran attacks it very clearly;
Quran 5:73 “They do blaspheme who say: Allah is one of three in a Trinity: …”