Augustine of Hippo

"My soul is athirst for the living God" (ver. 2). What I am saying, that "as the hart panteth after the water-brooks, so longs my soul after Thee, O God," means this, "My soul is athirst for the living God." For what is it athirst? "When shall I come and appear before God?" This it is for which I am athirst, to "come and to appear before Him." I am athirst in my pilgrimage, in my running; I shall be filled on my arrival. …

Exposition on Psalm 42 ↗

Gregory the Dialogist

First, therefore, he is sought without being found, so that afterward, when found, he may be held more tightly. For holy desires, as we have said, grow by delay. But if they fail by delay, they were not desires. With this love burned whoever was able to reach the truth. …

Forty Gospel Homilies, Homily 25 ↗

Thomas Aquinas

But is there a fountain of waters in God? Yes; hence he says, "My soul has thirsted for God, the living fountain." A fountain is called one that springs forth and produces living waters, and that unceasingly and unfailingly sends forth waters. Every water of graces flows from that fountain, namely from God the Father. Jer. 2: "They have forsaken the fountain of living water." Likewise it flows from the Son, also insofar as he is God. Ps. 36: "With you is the fountain of life." "The fountain of wisdom is the word of God," Sir. 1. …

Exposition on the Psalms of David ↗