Honestly, in today’s environment, convincing somebody of Jesus’ humanity is hardly difficult. If they believe he existed at all, people believe that Jesus is human. Nevertheless, it’s important to recognize that Jesus was a man for the sake of saving us. Hebrews 2 says that “he who sanctifies and those who are sanctified all have one origin… since the children share in flesh and blood, he himself took of the same things…. He had to be made like his brothers in every respect, so that he might become a merciful and faithful high priest in the service of God, to make propitiation for the sins of the people.” If any part of him is less than human, it is precisely in that area that his salvation is less than effective. With that in mind, it’s worthwhile still to examine him as he was examined in Jerusalem, to see if there is any “flaw” in him, that is, any inhumanness.
In 1st John 1:1, John makes it clear that Jesus was no phantom or figment of the apostles imaginations, but that he was “seen with [their] eyes… looked upon and… touched with [their] hands,” and they included ample evidence of this in the Gospels. Jesus had a normal birth (if not a normal conception), witness the birth narratives in Matthew and Luke. He had a real childhood. His family fled Judea when his life was threatened. He learned a real trade and had a real family in a real town, where he was not accepted as anything great, because they had seen him grow up. He had more than ample right to complain, like the Merchant of Venice, “If they prick us, do we not bleed?” For he did really bleed. And when he died, he really died.
Nevertheless, even if his physical being couldn’t be denied, some people might want to suppose that Jesus was some kind of super-man, who didn’t experience life the way we do, so that perhaps the physical experiences he encountered were made less pertinent by his superhuman experience of it. But this isn’t the witness of the gospels either. He experienced normal human emotions: He rejoiced with abandon when he was happy (Luke 10:21) and wept with real sorrow at the pain of death (John 11:35). He was thirsty on the cross (John 19:28) and rested when he became weary on a journey (John 4:6). Furthermore, he demonstrated real limits to his knowledge, about the time of his returning, about how much food was available in a crowd.
More importantly, he was tempted, yet without sin. Of course, the Gospels don’t attempt to catalogue every internal struggle with temptation, delving into his inner thoughts like a modernist novel. As a result, it’s much easier to recognize the “without sin” part than the “tempted in every way” part. But the gospels do record two key temptation incidences, and from there I think we can be acquire sufficient confidence about Jesus’ humanity in regards to temptation. First is the three temptations at the beginning of his ministry. Whole books have been written on this scene, and I won’t attempt to do anything so thorough, but I will point out that the temptation was significant enough to Jesus for him to relate the narrative at a later point to his disciples. Secondly, and more indicative is the temptation, before he was crucified, to pass up that crucifixion. Any reading of that narrative would clearly see that Jesus underwent an intense struggle with a very real temptation, as any man would when confronted with such an ordeal. If he did not fail in this matter, why would we suppose he might have failed elsewhere? And if he struggled so intensely over the preservation of his life, why would we suppose he wasn’t tempted in every other area, as all men are tempted?