It was impossible for Jesus to sin. In Luke 1:35, Mary was told “that holy thing” that will be conceived by the Holy Spirit is the Son of God. He was “holy, harmless, undefiled, separate from sinners” (Hebrews 7:26). It is rank heresy to say that Jesus Christ could sin or that He had any sin in Him. He was in all points like we are, except for one: He was not contaminated with sin.
Jesus was not tempted to see if He would fall. He was tempted to show that He could not fall: "The prince of this world comes, and has nothing in me" (John 14:30). After He had lived a life down here for thirty-three years, Satan came with this temptation, a temptation that appealed to man's total personality—the physical side, the mental side, and the spiritual side of man.
The Lord Jesus could not fall, and the testing was given to demonstrate that He could not fall. If He could have fallen, then any moment your salvation and mine is in doubt. The minute He yielded to sin, we would have no Savior. His temptation was to prove that He could not sin. These temptations that came to Him are the same temptations that come to us. But He did not fall because He could not fall.
Then someone is sure to argue, “Wait a minute. Then He must not have been tempted as we are.” He was tempted greater than we ever were tempted. You know, a boat out in the water can stand just so much pressure. As that pressure builds up the boat will finally give way, and when it does, then the pressure is relieved. When pressure is put on us, we finally give way and yield to the temptation. That is common knowledge, of course, and we live in a mean world today. Folk put temptation in the presence of a man who is very honorable and in front of some chaste, marvelous woman. They keep building up the pressure because they know there will come a time and a circumstance when those people will probably yield to it.
Now, the devil put all the pressure on the Lord Jesus that was possible to put on any creature, and the Lord Jesus withstood it. He could bear all that pressure. So, He has been tempted lots more than you and I have. He really knows what it is to be tempted. The difference is that you and I know what it is to be tempted and fall, but He did not experience that.
Taken from “If Jesus Could Not Sin, Why Was He Put in the Wilderness and Tested?” by Thru the Bible Ministries (used by permission).