Psalm 7 — God Has Prepared His Deadly Weapons

When certain people plot against you, as did Ahithophel against David, and you are informed of this, sing Psalm 7, and place your trust in God, who will deliver you..

Athanasius, On the Interpretation of the Psalms 15

Another lament. So many laments in a row. This one, though, has some interesting twists such as showing God threatening the enemy and the psalmist saying, "Hey I haven't been perfect in the past, but this time I definitely deserve justice."

7:6, The Fury of Enemies

Arise, he says, using the word to mean "appear"; he employs a human and obscure expression as though God were asleep, when really he is hidden and unrecognized in his secret plans.

St. Augustine, Expositions of the Psalms

Yes. How often does this happen to us too?

7:8, My Righteousness and Integrity

Not Perfect Righteousness. Theodoret of Cyr: In these words the divine David has not left a testimony to his own righteousness: we hear him protesting the opposite, "because I acknowledge my lawlessness, and my sin is always before me"; and, "I said, 'I shall declare my lawlessness against myself to the Lord,'" but he calls it justice in the matter before us. I committed no wrong, in fact, he is saying against Absalom or Ahithophel or those arrayed in battle with them against me. So I beg to be judged in the light of this righteousness and innocence and not in the light of the faults previously committed by me. I ask for judgment on these current grounds and not for a payment of penalty at this time for other sins.  Commentary on  the Psalms

Psalms 1-50 (Ancient Christian Commentary on Scripture)

This strikes me in the light of confession and being able to pick ourselves up, trust in God's forgiveness, and moving forward to try to do better.

7:12, God's Weapons Prepared

Yahweh prepares to mete out the punishment ... stringing and drawing the bow and preparing to let fly with flaming arrows at the enemy. This well-drawn portrait of the ready archer stops just short of release — bow straining, eye on the target; Yahweh is poised, ready to act. The picture encourages the enemies to reconsider their opposition in light of Yehweh's sure defense of the righteous.

Psalms Volume 1 (The NIV Application Commentary)

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I would happily understand [the bow in this verse] as the holy Scriptures, where the rigidity of the Old Testament is bent and subdued by the strength of the New Testament, as by some sort of bowstring. The apostles are launched from it like arrows, or divine proclamations are hurled from it. These arrows he has fashioned ... to make those who are struck by them blaze with the love of God. ... Once struck by these and set on fire by them, you must blaze with so great a love for the kingdom of heaven that you scorn the tongues of all who block your path and want to call you back from your fixed resolve. ...

St. Augustine, Expositions of the Psalms

I like the point that thinking of what Yahweh can unleash might make the enemy change his mind. How often I've had that same experience — often by considering that I'd have to confess a deed I was contemplating. Nothing like that for making you choose the righteous path instead of sin.

Sources are here and an index of psalm posts is here.