But as for me, I will walk in my integrity,
Redeem me, and be merciful to me.
But the Psalmist is not like that. His back is turned on corruption, and he intends to continue walking in integrity. And so he prays that YHWH will deliver him by an exertion of power at a cost to Himself, and will be merciful to him, so that he may prevail against those who are against him.