Then he said: “All my desire is before you” (Ps 38:9). He doesn’t say, “before men”–they can’t see hearts; he says, “Before you is all my desire.” Let your desire be before him, and the Father who sees what is hidden will reward you (Mtn 6:6) For your desire is your prayer, and if your desire is continuous, your prayer will be continuous. That’s why the Apostle said, “Pray without ceasing” (1 Th 5:17). We’re not always on our knees, are we, or prostrating ourselves, or lifting our hands, in order to do what Paul says, “Pray without ceasing”? If that’s the way we say we pray, I don’t think we can do it without ceasing. But there is another, an inner praying without ceasing, and that is desire. Whatever else you do, if you desire that sabbath, you do not cease to pray. If you don’t want to cease praying, don’t cease desiring. Your continuous desire is your continuous voice. You grow silent if you stop loving. Which people grew silent? The ones of whom it was said: “Because wickedness abounded, the charity of the many grew cold” (Mt 26:12). When charity is cold, the heart is silent. When charity is burning hot, the heart is shouting. If charity always remains, you are always shouting; if you are always shouting, you are always desiring; if you desire, you are remembering that sabbath rest. (Augustine, Enar. in Ps 37, 14; PL 36, 44)

[The two references to the sabbath appear because the Psalm-title in Augustine's version read: "A psalm for David: for a remembrance  of the sabbath," and he had already explained that this Psalm of lament was inspired in part by painful love and desire for a sabbath still to come.]