What doth the conclusion of the Lord’s Prayer teach us? – Shorter Westminster Catechism

The conclusion of the Lord’s Prayer, which is, For thine is the kingdom, and the power, and the glory, for ever, Amen. teacheth us to take our encouragement in prayer from God only, and in our prayers to praise him, ascribing kingdom, power, and glory to him ; and, in testimony of our desire, and assurance to be heard, we say, Amen.