In the second book of The Marrow of Theology, William Ames's (1576-1633) classic Post-Reformation work, Ames deals with a number of matters related to practical theology. The ninth chapter discusses prayer.1 As you will see, Ames's approach to this topic is helpful from a historical and practical perspective.
Prayer, Ames says, can be outward or inward–mental or audible. Audible prayer, properly speaking, should always be the expression of inward prayer. He explains, "The voice is the human organ of articulate speech which is often necessary to expression, stir up, continue, and increase an inward affection of the mind." Strictly speaking, the inward affection should come before the outward expression. Yet, as is so often the case, when the affection is spoken, the expression will often stir the affections up to an even greater extent.2 Moreover, God intended that the voice unify the soul and the body for religious exercises.
As is common with the Puritans, Ames regarded singing to be a form of prayer. You see, people pray audibly either in prose or in meter. Singing, of course, is metrical, and so the vocalization, by necessity, is much more controlled and deliberate. "The melody of singing is ordained for a certain kind of spiritual delight whereby the mind is held in meditation on the thing that is sung." It is important to note here that Ames emphasizes the spiritual delight from singing that comes when the mind clearly understands the content of the song. For Ames, singing should aid in such meditation. Such a "lifting up of the heart to God" is the goal of sung prayers.
Because singing is prayer, Ames disapproves of using "the decalogue and the like" as the text for songs, for such passages of Scripture are not, properly speaking, prayers.3 We sing with "bodily attitudes" that are different from those we use in prayer because singing builds believers up and displays the "joy of the mind." Ames disapproves of antiphonal singing because the voices are not all together; antiphonal singing does not as effectively lend itself to mutual edification and corporate affections.4 Moreover, Ames insists that "broken music which the mind cannot follow should be kept out of holy exercises, at least in those which we have with others" so that others understand our speech (here citing 1 Cor 14).
Ames's teaching benefits us. His distinction between inward and outward prayer helps us see the importance of conscious prayer. The connection between singing and praying is a good one for us to remember, and not highlighted enough in our day. He reminds us of the organic connection between body and soul, and that the actions of the body, whether by words or other actions, should never detract from the content of the prayer.
William Ames is my favorite.