John Calvin Commentary Psalms 9:3

"When mine enemies turn back, They stumble and perish at thy presence." — Psalms 9:3 (ASV)

While my enemies are turned back. In these words he assigns the reason why he undertakes to sing the praises of God: namely, because he acknowledges that his frequent victories had been achieved, not by his own power, nor by the power of his soldiers, but by the free favor of God.

In the first part of the verse, he narrates historically how his enemies were defeated or put to flight; and then he adds what faith alone could enable him to say: that this did not take place by the power of man or by chance, but because God fought for him and stood against them in the battle.

He says, they fall, and are put to flight At Thy Presence. David therefore acted wisely when, upon seeing his enemies turn their backs, he lifted up the eyes of his mind to God, in order to perceive that victory flowed to him from no other source than from the secret and incomprehensible aid of God.

And, doubtless, it is He only who guides the simple by the spirit of wisdom, while He inflicts madness on the crafty and strikes them with amazement—who inspires with courage the faint and timid, while He causes the boldest to tremble with fear—who restores to the feeble their strength, while He reduces the strong to weakness—who upholds the fainthearted by His power, while He makes the sword fall from the hands of the valiant—and finally, who brings the battle to a prosperous or disastrous issue, just as He pleases.

When, therefore, we see our enemies overthrown, we must beware of limiting our view to what is visible to the physical senses, like ungodly men, who, while they see with their bodily eyes, are yet blind; but let us instantly recall this truth: that when our enemies turn back, they are put to flight by the presence of the Lord.

The verbs, fall and put to flight, in the Hebrew, are in the future tense, but I have translated them in the present because David anew presents to his own view the goodness of God which had formerly been manifested towards him.