WCF 9.4.
When God converts a sinner, and translates him into the state of grace, He freeth him from his natural bondage under sin; (Col. 1:13, John 8:34, 36) and, by His grace alone, enables him freely to will and to do that which is spiritually good; (Phil. 2:13, Rom. 6:18, 22) yet so, that by reason of his remaining corruption, he doth not perfectly, nor only, will that which is good, but doth also will that which is evil. (Gal. 5:17, Rom. 7:15, 18–19, 21, 23)