I will also praise you with the psaltery, even your truth, O my God: unto you will I sing with the harp, O you Holy One of Israel.
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Augustine of Hippo
28. "For I will confess to Thee in the vessels of a Psalm Thy truth" (ver. 22). The vessels of a Psalm are a Psaltery. But what is a Psaltery? An instrument of wood and strings. What doth it signify? There is some difference between it and a harp: ...there seemeth to be signified by the Psaltery the Spirit, by the harp the flesh. And because he had spoken of two bringings back of ours from the bottomless places of the earth, one after the Spirit in hope, the other after the body in substance; hear thou of these two: "For I will confess to Thee in the vessels of a Psalm Thy truth." This after the Spirit: concerning the body what? "I will psalm to Thee on a harp, Holy One of Israel."