Heidelberg Q69

How is it signified and sealed unto thee in holy baptism that thou hast part in the one sacrifice of Christ on the cross? Thus: That Christ has appointed this outward washing with water, and by it promised, that I am as certainly washed with his blood and Spirit from all the pollution of my soul, that is, from all my sins, as I am washed outwardly with water, by which the filthiness of the body is commonly washed away.