WCF 28.6.
The efficacy of Baptism is not tied to that moment of time wherein it is administered; (John 3:5, 8) yet, notwithstanding, by the right use of this ordinance, the grace promised is not only offered, but really exhibited, and conferred, by the Holy Ghost, to such (whether of age or infants) as that grace belongeth unto, according to the counsel of God’s own will, in His appointed time. (Gal. 3:27, Tit. 3:5, Eph. 5:25–26, Acts 2:38, 41)