The psalmist doesn't lead with his case — he leads with an admission that undercuts any case he might make: “no one living is righteous before you.” That's a strange strategy if he's trying to be heard sympathetically. He isn't building an argument for why he deserves relief; he's removing that argument entirely before he even asks. And yet he still asks — the plea and the disqualification sit in the same two verses, unresolved by each other. That's the difficult part. Most of us wait until we feel like we have some standing before we ask for real help. This psalm asks anyway, precisely because it's addressed to God's faithfulness and righteousness, not the psalmist's own.