For follow-up discussion and general commentary on the topic. Comments are sorted chronologically.
Let's be clear about this 'Fully Man' thing.Every man conceived by man has a sin nature. He is fully man.
Jesus is said to be fully man and he didn't have a sin nature, because he wasn't conceived by a man.
So he is different from every other man.
Is he "fully man" in the sense that he's just like any other man? Of course not! So 'fully man' is a little bit of a misnomer. It is to be understood within reason.
It's similar to what was said about Adam and Eve, said to be "created in the image of God." That's to be understood within reason. They had a capacity to obey or disobey God. God doesn't have that capacity. The word says, "He remains faithful, for he cannot deny himself" (2 Tim 2:13). Listen to that! This is being said about Jesus. If Jesus is unfaithful to God he's unfaithful to himself. (the teachers here who say Jesus was capable of sin need to study that scripture until the light shines from it into your heart and mind).
It doesn't say that he won't, it says he can't! It says he remains faithful to himself.
You have to dismiss a truckload of scripture to teach that God can sin. You also have to dismiss a truckload of scripture to teach that Jesus isn't God!
Good question! To deny this possibility, some believe, would deny His full humanity, His ability to “sympathize with our weaknesses” (Heb. 4:15), and would make His temptation into a charade -- a farce.
--https://defendinginerrancy.com/bible-solutions/Hebrews_2.17-18.php
But I don't believe He was able to sin because He had no old sin nature like everyone else does. The temptations came his way, the outward temptations, but He had no inner compulsion to commit sin. And so He was able to overcome temptations. That's how I see it.
See Don Stewart at Blue Letter Bible for a full argument: https://www.blueletterbible.org/faq/don_stewart/don_stewart_1324.cfm
James 1:13 says God is not tempted to sin. Was not Jesus God and was He not tempted? The answer is “yes.” Jesus was tempted in His humanity but not in His deity. So, “Jesus was tempted” according to Hebrews 4:15 in his humanity. Jesus was not tempted according to James 1:13 in relationship with his deity. Dr. Tim White
Dr. Charles Ryrie, my professor of Theology at Dallas Theological seminary, makes this important distinction about the temptations of Christ: “Christ’s three different times of temptation were suited to the God/Man” (Charles Ryrie, Basic Theology, 305).