Galatians 6:8

Galatians 6:8 For he who sows unto his own flesh will reap corruption of the flesh, but he who sows unto the Spirit will of the Spirit reap eternal life.

To sow unto the flesh is to sow the flesh is to sow with a view to the flesh, or for the flesh, or for the flesh, with the purpose of the flesh in view, fulfilling what the flesh covets. To sow unto the Spirit is to sow for the Spirit, with the aim of the Spirit, accomplishing what the Spirit desires. To sow for the fulfilling of the purpose of the flesh issues in corruption; to sow for the accomplishing of the aim of the Spirit issues in life, even eternal life. Corruption is of the flesh, indicating that the flesh is corrupted; eternal life is of the Spirit and is the Spirit Himself. 

- "Life Study of Galatians" PP257-258