"For the mind set on the flesh is death, but the mind set on the Spirit is life and peace" Romans 8.6
To lean onto the flesh means fulfilling the desires of the heart, which is the source of misleading and prohibited feelings.
To lean onto the Spirit is to deny the feelings of the heart and practicing the discipline of faith.
The flesh hates discipline, order, justice, Bible, Law, fear of God, perseverance, Commandments, and everything else that pertains to spiritual values and that are contrary to the emotions of the heart.
