A traditional prayer recited before Lauds and Vespers in the Church’s Divine Office reads: “Open, O Lord, my mouth to bless Your holy name: cleanse my heart from all idle, distorted, and wandering thoughts; enlighten my understanding, set fire to my affections, and grant that I may be able to pray this office worthily, attentively, and with devotion, so that my prayer will be worthy of rising before your divine Majesty. Through Christ our Lord.”

I first learned this prayer in Latin at the Benedictine monastery of St. Anselmo, on the Aventine hill in Rome, and I have said it for years before praying the several offices in the Liturgy of the Hours. In a few brief words it expresses the thoughts that go through one’s mind at the beginning of a time of prayer. Prayer has to do not only with the words we say, but the disposition of the heart. Wandering thoughts and a distracted mind easily turn us away from the business at hand, but it is the heart that holds us to God. Hence the petitions: “cleanse my heart” and “set fire to my affections.” Without love, without a heart fixed on God, prayer is a futile exercise, words vanishing in the air.

The word “heart” appears frequently in the psalms. One day some years ago I began underlining it when I prayed the office. I was astonished at how often “heart” occurs in the psalms. Here are a few examples chosen at random:

“I will give thanks with my whole heart.” (Ps 9)

“My heart shall rejoice in thy salvation.”(Ps 13)

“I keep the Lord always before me. . . . Therefore my heart is glad, and my soul rejoices” (Ps 16).

“Let the words of my mouth and the meditation of my heart be acceptable in thy sight, O Lord, my rock and my redeemer” (Ps 19).

“Thou hast said, ‘Seek ye my face.’ My heart says to thee, “Thy face, Lord, do I seek.” (Ps 17).

“My heart became hot within me” (Ps 39).

“Create in me a clean heart, O God” (Ps 51)

My heart is firmly fixed, O God, my heart is fixed.” (Ps 57)

“Blessed are the men whose strength is in thee, in whose hearts are the highways to Zion” (Ps 84).

“Teach us to number our days that we may apply our hearts to wisdom” (Ps 90)

“I incline my heart to perform thy statutes” (Ps 119:112).

The activity of the heart even carries over into our sleep: “In the night my heart instructs me” (Ps 16). So the hymn sung at Compline, Te lucis ante terminum (“To thee before the close of day”), has these verses: :”Te corda nostra somnient, te per soporem sentient” (“Our hearts dream of you, they have you in mind while we sleep”).

The heart is the organ of prayer, even when we are not conscious of what we are doing. Unlike the mind, which is acquisitive, aggressive, and critical, the mark of the heart is receptivity, openness, love. It is a place to be filled, a thing to be ignited. The mind receives on its own terms, always filtering, discriminating, judging, but the heart is patient; it waits, watches, listens, making space for what it is to receive. Recall the line from “Amazing Grace”: “Twas grace that taught my heart to fear.” The heart delights not in its own cleverness, but in the presence of the beloved.

All the great spiritual writers in the Church’s history have known that without a heart ablaze with love for God our spiritual lives languish. For it is the heart that lifts us to God and holds us to God. When the soul is wounded by the piercing shafts of Christ’s love it offers love in return. In the famous passage at the beginning of Augustine’s Confessions, it is the “heart” that is restless till it rests in God. And later in the same book he says it is love that carried him to God. “By God’s gift we are set on fire and carried upwards; we grow hot and ascend. We climb ‘the ascents in our heart’” (Ps 83:6).

The work of prayer is tutoring the heart, a quite different thing from training the mind or disciplining the will. Prayer is an apprenticeship in keeping the great commandment, “You shall love the Lord your God with all your heart. . . .” It is a work without ending, as necessary to our inner life as the rhythm of breathing to our physical life. And it occupies us for a lifetime and beyond.

Commenting on the psalm verse, “I have hidden your words in my heart” (Ps 119:11), St. Bernard wrote: “Keep God’s word in this way. Let it enter into your very being, let it take possession of your desires and your life. Feed on goodness and your souls will delight in its richness. Remember to earn your bread in this way or your heart will wither away.”