Paul wrote to the Galatians: ”For the one who sows to his own flesh will from the flesh reap corruption, but the one who sows to the Spirit will from the Spirit reap eternal life.”
The first man to sow to his own flesh was Adam when he attempted to become like God by eating from the wrong tree. In reality this is the whole enchilada. Anyone who tries to improve himself according to a fixed set of laws, ordinances or whichever system that is based on the tree to knowledge of good and evil is in reality attempting to become like God. The corruption Paul speaks about is the curse that Adam faced after his fatal decision not to believe that he was created in God’s likeness and hence perfect in Him.
God said to Adam: “Cursed is the ground because of you; in pain you shall eat of it all the days of your life thorns and thistles it shall bring forth for you.” Ever from the beginning God has said that self-improvement is impossible; the ground is cursed. Attempt to please God by your own efforts and all you will bring forth are thorns and thistles. The thorns and thistles will sting you as condemnation and disappointment in yourself. Slowly but surely you are lead to the end of yourself. When the scripture speaks about carnal minded believers it refers to those who haven’t grasped who they are in Christ through faith, and thus struggle in their own powers to become righteous, that is, meet the standards they believe God has set up for them.
Those who sow to the Spirit are those who have embraced the truth and entered His rest where they rest from their own works. They know who they are in Christ and hence by faith daily experience the powers of the age to come, that is, eternal life.