WCF 16.1.
Good works are only such as God hath commanded in His holy Word, (Micah 6:8, Rom. 12:2, Heb. 13:21) and not such as, without the warrant thereof, are devised by men, out of blind zeal, or upon any pretence of good intention. (Matt. 15:9, Isa. 29:13, 1 Pet. 1:18, Rom. 10:2, John 16:2, 1 Sam. 15:21–23)