Trinity
The HolyTrinity:
Explanation to Muslims:
You believe that God is present: God the Father
You believe that God creates: God the Son (creates by His Word)
You believe that God is alive, not a dead object: God the Holy Spirit. The living God has a spirit, The Holy Spirit
Of course Christians believe in ONE GOD, it is the first thing said in the Creed. Three in one and one in three. If you deny the Holy Spirit, then you deny that God is a living God. If you deny Jesus, then you deny that God is the creator of all things, seen and unseen. Jesus is the Word of God. The Koran itself says that Jesus is a Word from Him; Him refering to God the Father, and Word refering to God the Son, the Word.
Simplest way to make you understand is the triangle, it has three sides.
Re The Holy Spirit: is mentioned repeatedly in the Koran
Re Jesus in Koran
1. Borne with no human seed, who else was like that? Adam, well, was created by God from mud. Jesus was a Spirit from God
2. Jesus himself created: He held mud and blow into it and it turned a bird
3. Koran says that: Jesus was not crucified but it appeared to them as if he was. Many interpretations to this verse, depending on what the commentator want to convey. Well, here it is for you: He was not killed because how can they kill God, but they thought they triumphed over him, thinking they ended his mission being hanged on the Cross. But how can you kill God! It was an illusion as far as they were concerned, that is the meaning. There is nothing in the Koran that somebody else was crucified in his place, just attempts of interpretation by different commentators.