Father Geiermann classifies prayer into three types: vocal, mental, and mixed:
“Vocal prayer is prayer expressed in words. Though no definite formula is necessary for vocal prayer, it is advisable to use the prayers approved by the Church to safeguard the piety of our prayer. Without piety, that is mistrust of self and confidence in God, the most profound sentiments that man could express would be emptiness if not arrogance in the sight of God.”
“Mental prayer is prayer of the mind and will without external words.” Mental prayer can be understood in both a wide sense and a restricted sense.
“In a wide sense it embraces all religious thoughts, desires, affections, and aspirations that man may have through life, as the result of reading spiritual books, hearing sermons, and association with pious persons. As such it enlightens the mind, disposes our hearts for the practice of virtue, and enables us to pray as we should. When understood in this sense, mental prayer is morally necessary for salvation, and indispensable to attain perfection.” The prophet said, “With desolation is all the land made desolate: because there is no one that considereth in the heart” (Jer 12:11).
“In a restricted sense mental prayer was called active contemplation by ancient spiritual writers, but is usually called meditation in our day. Meditation is mental prayer reduced to a system. As such it consists of three things: (1) the introduction, a more or less formal appearance of the soul in the presence of God; (2) the meditation proper; (3) the conclusion, an humble and grateful withdrawal of the soul from the Divine Presence.”
“The meditation proper consists (1) in the acts of the mind contemplating a truth of religion, preferably one of the eternal truths, or some phase of the life and suffering of our divine Saviour, and applying the same to ourselves; (2) in heartfelt affections and prayers which have been aroused by the considerations and applications; and (3) in a practical resolution of the will. . . . The affections we should elicit are especially acts of faith, of thanksgiving, of humility, of hope, of love, and of contrition. . . . The resolution we should form should be (1) a general one to avoid evil and to do good; (2) a particular one to avoid some special evil or danger, or to practise some particular virtue.”
“Mixed prayer is a union of vocal and mental prayer. Every vocal prayer may be made a mixed prayer with great profit to the soul by pausing at the words or sentiments that particularly appeal to us, to make appropriate affections.” Two popular mixed prayers are the Rosary and the Way of the Cross, both of which involve the recitation of prayers while meditating on the mysteries alluded to in those prayers.
Quotations from Peter Geiermann, The Narrow Way (New York: Benziger, 1914).