Westminster Larger Catechism in modern English question number thirty-four:
Q. 34. 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 all foreshadowed the Christ who was to come. For that time, these things were sufficient to build up the faith of the elect in the promised Messiah, in whom they even then had full forgiveness of sin and eternal salvation.