How do the sacraments become effectual means of salvation? – Shorter Westminster Catechism

The sacraments become effectual means of salvation, not from any virtue in them, or in him that doth administer them; but only by the blessing of Christ, and the working of his Spirit in them that by faith receive them.

Shorter Westminster Catechism

How is the Word to be read and heard, that it may become effectual to salvation? – Shorter Westminster Catechism

What is a sacrament? – Shorter Westminster Catechism