Levítico 15

Levítico 15:5

The washing which is common to all persons is that of the baths, which usually cleanses away the filth of the body. There is also the washing of the Jews, which is more solemn than that of the baths but much inferior to the bath of grace. While this [baptismal] bath cleanses bodily filth, it does not merely remove the uncleanness of the body but also that which clings to a weak conscience. — BAPTISMAL INSTRUCTIONS 9.13