Because Islam rejects the Deity of Christ, it's a common vector of attack for Muslim apologists, who make a point to try to use the Bible to prove that Jesus wasn't divine.
This article will deal with the most common arguments of this type made by Muslims.
Ahmed Deedat and Zakir Naik, for decades, have been training Muslims to ask Christians the question - "Where did Jesus say, I am God, worship me, in those exact words?"
The question has a number of evident problems:
The Bible unequivocally records Jesus dying (Matthew 27:50, Mark 15:37, John 19:30, Revelation 1:18, etc.), and of course, rising from the dead as well (Matthew 28:6, Luke 24:6: 1 Corinthians 15:3-4, etc.).
But if Jesus is God, how could God "die"?
Well, what is the definition of "death"? Does it mean "cease to exist"? No, rather, the Biblical definition of death is the spirit leaving the body:
James 2:26
26 For as the body without the spirit is dead, so faith without works is dead also.
In all of the accounts of Christ's death, this is precisely what is described:
Luke 23:46
46 And when Jesus had cried with a loud voice, he said, Father, into thy hands I commend my spirit: and having said thus, he gave up the ghost.
Therefore, this is not at odds with any claim about Christ's divinity. His body was without His spirit, for three days and three nights (Matthew 12:40).
During the incarnation, Jesus prayed (Matthew 14:23, 26:36, etc.), and even now, Jesus prays (Romans 8:34, Hebrews 7:25).
But if Jesus is God, who is He praying to?
This question misunderstands or misrepresents the Christian view of God. Trinitarian Christians don't believe in a Modalistic God, or a Unitarian God like Allah. Such a concept of God is false, because there is only one God, and that God is Father, Son, and Holy Spirit, who are not each other, and yet all three are one God. That's what the doctrine of the Trinity teaches.
Therefore, we don't believe that Jesus is praying to himself. That straw man can go away now. It has never been true, and is slander.
Instead, Christianity teaches that Christ prays to the Father, as we see in the following examples:
John 11:41-42
41 Then they took away the stone from the place where the dead was laid. And Jesus lifted up his eyes, and said, Father, I thank thee that thou hast heard me.
42 And I knew that thou hearest me always: but because of the people which stand by I said it, that they may believe that thou hast sent me.
John 17:1
1 These words spake Jesus, and lifted up his eyes to heaven, and said, Father, the hour is come; glorify thy Son, that thy Son also may glorify thee:
This is one member of the Trinity communicating with another member. This communication is part of what makes them distinct from one another. Of course, if God were Unitarian, like the false god Allah, there would be no such communication.
Jesus, when speaking of His second coming, said that even He did not know the date it would take place:
Mark 13:32
32 But of that day and that hour knoweth no man, no, not the angels which are in heaven, neither the Son, but the Father.
I have an entire article devoted to answering this objection, so please refer to it for a more complete answer.
In short, Jesus chose to limit himself in many ways during the incarnation, both in omniscience, and omnipotence. The fact that Jesus allowed himself to have to work a job is a simple example of Him limiting His omnipotence, for the purposes that He was here to achieve - living a sinless life, and then dying for the sins of mankind (Hebrews 2:9, Philippians 2:5-8).
These were temporary, self-imposed limitations during the incarnation. Right now, in His glorified state, at the right hand of God (1 Peter 3:22), Jesus has "all power in Heaven and in earth" (Matthew 28:18), and knows precisely when His second coming will occur.
In two verses in John chapter 5, Jesus said something that Muslims construe as Christ declaring that He was a mere human being:
John 5:19, 30
19 Then answered Jesus and said unto them, Verily, verily, I say unto you, The Son can do nothing of himself, but what he seeth the Father do: for what things soever he doeth, these also doeth the Son likewise.
30 I can of mine own self do nothing: as I hear, I judge: and my judgment is just; because I seek not mine own will, but the will of the Father which hath sent me.
However, both the verses themselves, and the entire context of John 5, demonstrate that such an interpretation is dishonest, and ridiculous. It's more willful ignorance of context, and Trinitarian theology.
In both of the above verses, Christ mentions that He acts in accordance with the Father's will, rather than independently, or contrary to the Father - "I seek not my own will, but the will of the Father which has sent me". This is once again, a known, accepted part of Trinitarian theology - the son's submission to the Father:
1 Corinthians 11:3
3 But I would have you know, that the head of every man is Christ; and the head of the woman is the man; and the head of Christ is God.
John 6:38
38 For I came down from heaven, not to do mine own will, but the will of him that sent me.
John 8:29
29 And he that sent me is with me: the Father hath not left me alone; for I do always those things that please him.
Luke 22:42
42 Saying, Father, if thou be willing, remove this cup from me: nevertheless not my will, but thine, be done.
Christ submits His will to the Father, and the Father uses that submission to work through the Son. This submission is a fundamental part of their relationship, and once again, a well-known, understood part of Trinitarian theology.
This doctrine is the subject of a large portion of John chapter 5, including the interlude between the two verses in question:
John 5:20-26
20 For the Father loveth the Son, and sheweth him all things that himself doeth: and he will shew him greater works than these, that ye may marvel.
21 For as the Father raiseth up the dead, and quickeneth them; even so the Son quickeneth whom he will.
22 For the Father judgeth no man, but hath committed all judgment unto the Son:
23 That all men should honour the Son, even as they honour the Father. He that honoureth not the Son honoureth not the Father which hath sent him.
24 Verily, verily, I say unto you, He that heareth my word, and believeth on him that sent me, hath everlasting life, and shall not come into condemnation; but is passed from death unto life.
25 Verily, verily, I say unto you, The hour is coming, and now is, when the dead shall hear the voice of the Son of God: and they that hear shall live.
26 For as the Father hath life in himself; so hath he given to the Son to have life in himself;
In no sense does the context of the verses in question impart the idea that Christ was claiming that He was just a "mere human being". That interpretation could only exist as a product of deliberate deception, and willful ignorance.
In summary, Christ can do "nothing of himself", because the Father works through Him, and He does the Father's will. He is not a "separate God", nor does He do anything in opposition to the Father.
In John chapter 14, Jesus said that the Father was "greater" than He was:
John 14:28
28 Ye have heard how I said unto you, I go away, and come again unto you. If ye loved me, ye would rejoice, because I said, I go unto the Father: for my Father is greater than I.
In light of the previous section, the above verse falls into place, alongside all of the others which clearly teach the authority structure in the Trinity, with the Son submitting to the Father.
The Father is "greater" in authority, and the Son always obeys. This is not a statement denying that they are equal in their eternality, power, perfection, and so on.
Jesus made multiple statements in which He said that He had a "God", for instance:
John 20:17
17 Jesus saith unto her, Touch me not; for I am not yet ascended to my Father: but go to my brethren, and say unto them, I ascend unto my Father, and your Father; and to my God, and your God.
Matthew 27:46
46 And about the ninth hour Jesus cried with a loud voice, saying, Eli, Eli, lama sabachthani? that is to say, My God, my God, why hast thou forsaken me?
Jesus saying that He had a "God" does not contradict any aspect of the Deity of Christ, as taught in light of the Trinity. These are, once again, statements that serve to establish that He is not a "separate God", or somehow breaking with what was taught about God in the Old Testament, namely, that there is one God (Isaiah 43:10, etc.). This fact is confirmed just as clearly in the New Testament (1 Timothy 2:5, etc.), and does not contravene the Deity of Christ.
This is further evidenced by passages like Hebrews 1:8-9, which both calls Jesus "God", and acknowledges that He has a God:
Hebrews 1:8-9
8 But unto the Son he saith, Thy throne, O God, is for ever and ever: a sceptre of righteousness is the sceptre of thy kingdom.
9 Thou hast loved righteousness, and hated iniquity; therefore God, even thy God, hath anointed thee with the oil of gladness above thy fellows.
Above, "God" is anointing "God". The Trinity is not a Roman Catholic invention. It is a crystal-clear Bible doctrine, taught in hundreds of passages of Scripture.
So, God can have a God, because God is not Unitarian, and Jesus coming to earth did not suddenly make Him an Atheist. Any member of the Trinity can call any other member "God", without contradicting any part of Trinitarian theology.
On the cross, Jesus cried out:
Matthew 27:46
46 And about the ninth hour Jesus cried with a loud voice, saying, Eli, Eli, lama sabachthani? that is to say, My God, my God, why hast thou forsaken me?
Why was Jesus forsaken by God, and how is such a thing possible?
Jesus spoke of being "forsaken" by God, because on the cross, He was "bearing our sins in His own body" (1 Peter 2:24: 2 Corinthians 5:21), just as prophesied so clearly in the Old Testament (Isaiah 52:13-53:12). He was "being made a curse for us" (Galatians 3:13), to satisfy the penalty for our sins.
Many Muslims, ignorant of their own Scriptures, object to this as unjust. However, the Hadith says that all of the sins of Muslims will be put on the Jews and Christians, and that every Muslim will be swapped for a Jew or a Christian, who will be their deliverance from Hellfire (Sahih Muslim 2767a-b, 2767d).
The doctrine of Penal Substitutionary Atonement - covered in its own article here - has firm roots dating back to the very beginning of the Old Testament. The faulty Muslim view of atonement does not cast aspersions on God, but the critic.
The above explains why God put our sins upon Jesus Christ - to redeem mankind, by paying the debt that we owed. The answer as to how God could do this, if Jesus is God, is once again the fact that Jesus is not God the Father. The Muslim caricature of "God sacrificing himself to himself" is not only blasphemous, but also demonstrative of someone who is willfully ignorant, and too dishonest to attempt to fairly represent those they disagree with. Jesus is not the Father.
Jesus, while praying to the Father, said:
John 17:3
3 And this is life eternal, that they might know thee the only true God, and Jesus Christ, whom thou hast sent.
Above, Jesus says that the Father is the "only true God", and then draws a distinction between himself and the Father.
Once again, this fits well into the Christian understanding of the Triune God. There is one God, and that God is the "only true God". This is affirmed many times in the New Testament, for instance:
1 Timothy 2:5
5 For there is one God, and one mediator between God and men, the man Christ Jesus;
As in the previous section, because of the reality of the Trinity, any member of the Trinity could call any other member "the only true God", because they all constitute the only God there is.
The Trinity teaches that there are three Persons that constitute one God, and this allows them to make distinctions between each other, such as the one made in the passage in question. Muslims need to stop reading our Scripture with their Unitarian lense, and stop foisting that false, Unitarian position on our Bible, and then crying out when they find something that contradicts that misgiven presupposition.
Jesus, when speaking to the rich young ruler, said:
Mark 10:18
18 And Jesus said unto him, Why callest thou me good? there is none good but one, that is, God.
Muslims see this as Christ denying His deity, when in reality, it establishes His deity. Notice what Christ called himself in John chapter 10:
John 10:11, 14
11 I am the good shepherd: the good shepherd giveth his life for the sheep.
14 I am the good shepherd, and know my sheep, and am known of mine.
Christ is the "good shepherd", because Scripture is unequivocal in stating that He was utterly sinless (John 8:46: 2 Corinthians 5:21, Hebrews 4:15: 1 Peter 2:21-22: 1 John 3:5). Therefore, He is "good" in the absolute sense, meaning "perfect" - the sense which He says only applies to God, in the passage in question.
While this passage with the rich young ruler is the focus of another article, in short, the purpose of Christ saying this to the young man was to show him his sin (Ecclesiastes 7:20, Romans 3:10-12, etc.), and how far short he fell of God's standard (Romans 3:23).
Finally, if Jesus is God, why did He say things like:
John 1:18
18 No man hath seen God at any time; the only begotten Son, which is in the bosom of the Father, he hath declared him.
John 4:24
24 God is a Spirit: and they that worship him must worship him in spirit and in truth.
Firstly, we can recognize that since "No man hath seen God at any time", yet the Son has, it proves that the Son is not a mere ordinary man:
John 6:46
46 Not that any man hath seen the Father, save he which is of God, he hath seen the Father.
The above is just one of many hundreds of examples that demonstrate how dishonest, and foolish it is to try to use the Bible to support the Muslim view of God or Jesus. They are utterly at odds, in dozens of distinct ways. Yet, Muslims insist on playing this game, because they have to, as their prophet put them in an irreconcilable position by claiming that the Bible was sent from God, and he affirmed it, when he was a lying false prophet, who had no idea what he was talking about.
However, returning to the verses in question, Jesus Christ was referring to God the Father when He said that "no man has seen God", because the Father is clear that no man can see His face and live (Exodus 33:20). This would have been a great mystery in the Old Testament, as many people saw "the Lord" in the Old Testament (see this article for many examples), and even knew Him "face to face" (Genesis 32:30, Deuteronomy 5:4, 34:10).
This is explained in, once again, the doctrine of the Trinity, and pre-incarnate appearances of Jesus Christ, who is not the Father. Are you seeing the pattern by now?
Nearly all of these objections stem from misunderstanding, or misrepresenting, the Christian doctrine of the Triune God. Muslim apologists know this, and still repeat these objections, because they don't want to understand our view of God, and have no interest in representing what we believe fairly to their followers. They purposely slander and malign us, because they are the apostles of a Satanic false religion, and Satan is the father of lies (John 8:44).
However, all of these objections have very clear, very understandable resolutions within well-known and widely-accepted Trinitarian understandings of God. None of them present a problem to Biblical Christianity.
I have two articles dedicated to defending the Trinity, and the Deity of Christ, if you'd like further reading on the topics: