Roman Catechism 42.20

Chapter 42 — Part IV: Prayer — Amen

Section 20. Advantages of Terminating our Prayer with this Word — To us also this word is very appropriate, containing, as it does, some confirmation of the Petitions which we have already offered up. It also fixes our attention when we are engaged in holy prayer; for it frequently happens that in prayer a variety of distracting thoughts divert the mind to other objects.