Why spiritual disciplines?
“The aim of disciplines in the spiritual life–and, specifically, in the following of Christ–is the transformation of the total state of the soul. It is the renewal of the whole person from the inside, involving differences in thought, feeling, and character that may never be manifest in outward behavior at all. This is what Paul has in mind when he speaks of putting off the old man and putting on the new, ‘renewed to resemble in knowledge the one who created us…’ (Colossians 3:10)”
-Dallas Willard, The Great Omission, p. 151-2