Q. Was the covenant of grace always administered after one and the same manner?
A. The covenant of grace was not always administered after the same manner, but the administrations of it under the Old Testament were different from those under the New.
Q. How was the covenant of grace administered under the Old Testament?
A. The covenant of grace was administered under the Old Testament, by promises, prophecies, sacrifices, circumcision, the passover, and other types and ordinances, which did all fore-signify Christ then to come, and were for that time sufficient to build up the elect in faith in the promised Messiah, by whom they then had full remission of sin, and eternal salvation.
Q. How is the covenant of grace administered under the New Testament?
A. Under the New Testament, when Christ the substance was exhibited, the same covenant of grace was and still is to be administered in the preaching of the Word, and the administration of the sacraments of Baptism and the Lord’s Supper; in which grace and salvation are held forth in more fulness, evidence, and efficacy, to all nations.
(Questions XXXIII, XXXVI and XXXV of the Westminster Larger Catechism.)