Augustine of Hippo

And that it might be clear that the already perfect soul, which is to be on her guard against the most insidious snares of the devil only, says this, see what follows. "O Lord my God, if I have done this" [Psalm 7:3]. What is it that he calls "this"? Since he does not mention the sin by name, are we to understand sin generally? If this sense displease us, we may take that to be meant which follows: as if we had asked, what is this that you say, "this"? …

Exposition on Psalm 7 ↗

Jerome

'O Lord my God, if I have done this.' 'Behold, the prince of this world comes, and finds nothing in me.' 'If there be iniquity in my hands.' 'Who did no sin, neither was guile found in his mouth.'

Homily 3, on Psalm 7 ↗

Thomas Aquinas

Then he alleges his innocence: "O Lord my God, if I have done this." And this can be understood in two ways: either by way of an oath or of a prediction. If by way of an oath, then it should be known that there is a twofold oath: namely by attestation, as in Rom. 1: "God is my witness, whom I serve in my spirit," etc.; and by imprecation, as when one says, "If I have done this, may this befall me." Job 31: "If I rejoiced at the ruin of him who hated me," etc. 2 Cor. …

Exposition on the Psalms of David ↗