John Gill

But as for me, I will walk in mine integrity,.... In which he had hitherto walked, Psa 26:1; or it may express his faith, that after he was gathered by death he should walk in uprightness and righteousness, in purity and perfection, with Christ in white, and behold the face of God in righteousness; see Isa 57:1; redeem me; from the vain conversation of the wicked, from all troubles, and out of the hands of all enemies; and be merciful unto me; who was now in distress, being persecuted by Saul, and at a distance from the house of God: this shows that mercy is the source and spring of redemption, both temporal and spiritual; and that the psalmist did not trust in and depend upon his present upright walk and conversation, but in redemption by Christ, and upon the mercy of God in Christ.