WCF 27.3.
The grace which is exhibited in or by the sacraments rightly used, is not conferred by any power in them; neither doth the efficacy of a sacrament depend upon the piety or intention of him that doth administer it: (Rom. 2:28–29, 1 Pet. 3:21) but upon the work of the Spirit, (Matt. 3:11, 1 Cor. 12:13) and the word of institution, which contains, together with a precept authorizing the use thereof, a promise of benefit to worthy receivers. (Matt. 26:27–28, Matt. 28:19–20)