David alludes to the Exodus 34:6 in the confession that God is “good and forgiving, abounding in steadfast love” (Psalm 86:5). This takes us back to the holy event when God “drove the stake in the ground” about his identity. The LORD proclaimed his name. Essential to who he is—and unique from every competitor— is his immeasurable grace, his mercy, his covenant loyalty.
David takes us there in Psalm 86—David takes us there. He knows about God’s faithfulness and sure promise (2 Samuel 7:16), and he connects the dots for us here. God’s faithfulness to Abraham became God’s faithfulness to Moses and a wandering Israel, which became God’s faithfulness to his anointed king, David. And God’s faithfulness to David becomes faithfulness to us when we believe on his son and Lord (Psalm 110:1), the One crucified, dead, and buried, the One risen and enthroned on Zion as God’s eternal King.
Our petitions to the Father in Jesus’ name are in the same stream of God’s faithfulness. David prayed in reference to the promise and now we pray in reference to the person.
For, LORD, you are good and you are forgiving, you do abound in steadfast love, all through the death and resurrection of your Son in whom all your promises find their Amen!