Heidelberg Catechism – Lord’s Day 26
Q. How does holy Baptism remind and assure you that the one sacrifice of Christ on the cross avails for you?
A. In this way: Christ instituted this external washing with water and by it has promised that I am as certainly washed with his blood and Spirit from the uncleanness of my soul and from all my sins, as I am washed externally with water which is used to remove the dirt from my body.
Q. What does it mean to be washed with the blood and Spirit of Christ?
A. It means to have the forgiveness of sins from God, through grace, for the sake of Christ’s blood which he shed for us in his sacrifice of the cross, and also to be renewed by the Holy Spirit and sanctified as members of Christ, so that we may more and more die unto sin and live in a consecrated and blameless way.
Q. Where has Christ promised that we are as certainly washed with his blood and Spirit as with the water of baptism?
A. In the institution of Baptism which runs thus: “Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit.” “He who believes and is baptized will be saved: but he who does not believe will be condemned.” This promise is also repeated where the Scriptures call baptism “the water of rebirth” and the washing away of sins.