Temptation

 ⁴¹Watch and pray, that ye enter not into temptation: the spirit indeed is willing, but the flesh is weak. (Matthew 26:41, King James Version)

When the Lord speaks of the flesh being weak, it may mean that inside, in our renewed hearts and spirit, we want to live a righteous life.

But we are trapped in a prison of flesh that is driven by our lusts and our selfish desires.

The apostle Paul expands on this thought in the following passage:

 ¹⁷For the flesh lusteth against the Spirit, and the Spirit against the flesh: and these are contrary the one to the other: so that ye cannot do the things that ye would. (Galatians 5:17, King James Version)