The Westminster Standards on Baptism:
Baptism is a sacrament of the New Testament, wherein Christ has ordained the washing with water in the name of the Father, and of the Son, and of the Holy Spriit, to be a sign and seal of the ingrafting into himself, of remission of sin by his blood, and regeneration by his Spriit; of adoption, and resurrection unto everlasting life; and whereby the parties baptized are solemnly admitted into the visible Church, and enter into an open and professed engagement to be wholly and only the Lord's.