We believe and confess that Jesus Christ ... having abolished circumcision, which was done with blood, has instituted the sacrament of baptism, instead ...
by which we are received into the Church of God, and separated from all other people and strange religions, that we may wholly belong to him ...
Therefore he has commanded all those, who are his, to be baptized with pure water, "in the name of the Father, and of the Son, and of the Holy Ghost" ...
signifying ... that as water washes away the filth of the body, when poured upon it, and is seen on the body of the baptized, when sprinkled upon him; so does the blood of Christ, by the power of the Holy Ghost, internally sprinkle the soul, cleanse it from its sins, and regenerate us from children of wrath, unto children of God...
Not that this is effected by the external water, but by the sprinkling of the precious blood of the Son of God; who is our Red Sea, through which we must pass, to escape the tyranny of Pharaoh, that is, the devil, and to enter into the spiritual land of Canaan...
our Lord gives that which is signified by the sacrament, namely, the gifts and invisible grace; washing, cleansing and purging our souls of all filth and unrighteousness; renewing our hearts, and filling them with all comfort; giving unto us a true assurance of his fatherly goodness; putting on us the new man, and putting off the old man with all his deeds... (Belgic Confession 34)