Question:Was Jesus fully human when he was born into this world and could he have sinned?
In discussing Jesus, the writer of Hebrews stated, "Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, ... Therefore, in all things He had to be made like His brethren, that He might be a merciful and faithful High Priest in things pertaining to God, to make propitiation for the sins of the people. For in that He Himself has suffered, being tempted, He is able to aid those who are tempted" (Hebrews 2:14,17-18).
Luke recounted details of the birth of Jesus, as a human child to a human mother, so we might know that Jesus was human. His lineage is traced back to Adam, just as all of mankind can be, to show that he is the Son of Man. "The Son of Man must suffer many things, and be rejected by the elders and chief priests and scribes, and be killed, and be raised the third day" (Luke 9:22).
Being in the flesh, Jesus faced temptations, just like every other person. "For we do not have a High Priest who cannot sympathize with our weaknesses, but was in all points tempted as we are, yet without sin" (Hebrews 4:15). The potential to sin was always there. Sin is the breaking of law (I John 3:4). Temptation is the enticement to break God's law (James 1:13-16). You cannot be tempted by something you cannot do. Jesus had the choice to break God's law, but he consistently chose to do His Father's will -- unlike the rest of us. His life proves that no man has to sin. And by not sinning, he became the only and perfect sacrifice to free men from their sins (I Peter 1:18-19).
The importance of understand that Jesus came into this world to live as a man is so critical, that John pointed out:
"By this you know the Spirit of God: Every spirit that confesses that Jesus Christ has come in the flesh is of God, and every spirit that does not confess that Jesus Christ has come in the flesh is not of God. And this is the spirit of the Antichrist, which you have heard was coming, and is now already in the world" (I John 4:2-3).
"For many deceivers have gone out into the world who do not confess Jesus Christ as coming in the flesh. This is a deceiver and an antichrist" (II John 7).
We have a strong tendency to categorize things. If we place Jesus in the category of deity, we reject the fact that he was human. If we place Jesus in the category of man, we reject the fact that he is God. The truth revealed in the Scriptures is that Jesus is both the Son of God and the Son of Man; he is God who came to earth to share humanity with his creation.
"Let this mind be in you which was also in Christ Jesus, who, being in the form of God, did not consider it robbery to be equal with God, but made Himself of no reputation, taking the form of a bondservant, and coming in the likeness of men. And being found in appearance as a man, He humbled Himself and became obedient to the point of death, even the death of the cross" (Philippians 2:5-8).
"For there is one God and one Mediator between God and men, the Man Christ Jesus" (II Timothy 2:5).
"But now Christ is risen from the dead, and has become the firstfruits of those who have fallen asleep. For since by man came death, by Man also came the resurrection of the dead" (I Corinthians 15:20-21).