Jesus Christ is our great High Priest, and Hebrews 4:15 tells us that “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.”
Jesus sympathizes with weakness, but not with sin. He is unable to sympathize with sin. To be subject to temptation is weakness, but sin is more than just being subject to temptation. Sin is rebellion. It is not so much a weakness as it is the end of the weakness of being tempted.
What we hate about being tempted is that it makes us feel weak. We do not want to be tempted but are powerless to stop it. Sometimes it seems that the only way to stop the temptation is to yield to it.
We describe this yielding with passive words like “being overcome” and “being defeated.” But yielding to temptation is more than passively being conquered; it is active agreement with the tempter. We sin in order to end the temptation and the feeling of weakness that it brings.
This is the offer that the tempter makes to you: “Agree with me and end the weakness, or the temptation will never end.”
Do not take the offer. Remain in weakness. The temptation will end. It ended for Jesus in His death and it will end for you. But if you take the offer and agree with sin, the temptation will only end for a short while. It will come back stronger than ever. You will be troubled by the same temptation for the rest of your life.
The tempter can’t be bargained with, only resisted. As Thomas a Kempis has written, “We find our peace only by resisting our passions, not by giving in to them.”
Sin will lose its appeal to you. The temptation will go away by itself. It will come back, but not always in the same form. It will change over time. Your temptations will change to be conformed to Christ’s. No longer will there be cravings for petty indulgences and transient pleasures. As your heart is changed your desires will be purified. What once tempted you will lose all power over you. Your High Priest will help you.
The form of temptation will change but the weakness will remain. Jesus will bring an end to sin in your life. But He will not end the weakness. He will sympathize with it but He will not end it.
The weakness will remain. You cannot end the weakness. It is not ended by sinning, but by dying. Let Jesus claim it as His own. Suffering in this life is inevitable. Therefore, as Peter said (in 1 Peter 4:14-16) let it be for following Jesus that you suffer, not for sinning.
This is an excerpt from The Natural Holiness of Jesus
 Thomas a Kempis, The Imitation of Christ, Book One, Chapter Six, Catholic Book Publishing, 1977, p.24