Let's look at this verse:
And He went a little farther, and fell on His face and prayed, saying, “O My Father, if it be possible, let this cup pass from Me; nevertheless, not as I will, but as Thou wilt.”
--Matt 26:39
The Muslim may quote this verse to say that they pray as Jesus did.
And yet the same verse contradicts Islam when Jesus calls God "Father".
This is well worth pointing out as it is very hard for a Muslim to explain why the part of this verse that supports his case is true while the part of the verse that contradicts his case is a fabrication or error of some kind. There is no consistent methodology to do this, unless you just take the Quran as true in the first place.
Watch for this type of faulty argument. Muslims do this often.
Also, I have made a mistake that I suggest you try to avoid: I showed a Muslim verses where Jesus said things that supported the Trinity.
In his mind my purpose was to demonstrate that the Jesus taught the doctrine of the Trinity, so he responded by showing me arguments from non-Trinitarians like Jehovah's witnesses.
Actually, my purpose is to show that Jesus made statements that are contrary to what the Jesus of the Quran would have made. Sometimes we can find non-Trinitarian interpretations to what Jesus said, but since there is the Trinitarian interpretation of the statement, then what Jesus said is at the edge of blasphemy (unless it is true).
Eventually I realized this confusion and clarified this.
It is important to explicitly point out the contradiction between the the Quran's view and what we have from the historical record from the first century. The Quran does not make many refutable statements, so make use of this opportunity!
