If you search the English bible for "Jesus said, I am God", then you will not find these exact words in that order. So does that mean that he has never self-consciously thought or claimed he is God? Far from it. Jesus made numerous claims that only God can make. Here are his major ten claims to deity.

(1) In the parable of the weeds, Jesus said he would send "his angels" while taking about the Kingdom of God as "his kingdom" (Matthew 13:41). Angels are necessarily "the angels of God" (Luke 12:8-9; 15:10).

(2) Jesus readily forgave sins, while the Jew understood that no man could do that (Mark 2:5-10; John 8:11).

(3) Jesus said he would "judge the world" (Matthew 25:31-46). No man can have that kind of authority.

(4) Jesus said, "the Son of Man is Lord even of the Sabbath" (Mark 2:27-28). Unless he is God, he has no such authority to overrule the sacred Sabbath (Exodus 20:8-11). Jews of his time also understood that to mean he was equal with God (John 5:18).

(5) Jesus claimed oneness (in equality) with God (John 10:30, I and Father are one), to see and know him is to see and know the Father (John 14:7-9).

(6) Jesus claimed his preexistence (John 8:58, before Abraham was born, I am!). This "I AM" claim (also see John 8:24, 28) was most naturally understood to mean God (Exodus 3:14-15) by the Jews who became indignant of such naked blasphemy and attempted to stone him (John 8:59).

(7) Jesus affirmed that he indeed is the Christ and the Son of God (Matthew 26:63; John 19:7). The high priest understood clearly that Jesus had spoken blasphemy worthy of death (Matthew 26:65-66).

(8) Jesus accepted worship due properly only to God. For example, the doubting Thomas exclaimed when face to face with the risen Jesus: My Lord and my God (John 20:28).

(9) Jesus elevated his words to be that of God by frequently saying: you have heard that it was said, ...But I tell you..." (e.g., Matthew 5:21-22. 27-28).

(10) Jesus claimed divine power over life and death (John 5:21; 11:25).

Besides Jesus's self-conscious claims to deity, the NT bible expressly proclaim Jesus as Lord, God, savior, Christ.

Lastly, his resurrection (disputed by Muslims) proved his deity and all he claimed to be.

You may wish to point out to the Muslim friend that Koran clearly affirmed the virgin birth of Jesus Christ (and he was able to speak to Mary right after birth!). While Koran denied Jesus ever died on the Cross, Koran nevertheless affirmed his direct ascension to heaven and his coming in the end time to judge the world. So one cannot help but wondering who on earth and in heaven this Jesus (born of a virgin, ascended to heaven, with only an empty tomb for visitors, and to come again to judge all) is, while Mohammed was born of human parents and died and buried in Meca, revered in his death by millions of pilgrims every year.

Of course, you Muslim friend may attempt to deny the full authenticity of the NT (and OT) bible by saying that it is corrupted and thus untrustworthy. In that case, you need to understand how Bible and Koran were written and canonized and what Bible and Koran are teaching. Consult Norman Geisler's Answering Muslim (2nd edition) and Josh McDowell's the New Evidence that Demands a Verdict, as well as books by Muslim turned Christian authors. Read both Bible and Koran too.

Many muslims come to know Christ due to Christian friendship and witness, and sometimes personal miraculous encounter in dream or vision with the risen Christ. So pray for him. God bless your witness to Muslim friends.