What does Psalm 51:1 mean?
In many of David's psalms he addresses God as "my God," but his sin had removed him from close fellowship with God, so in this verse he prays, "O God." David knew God well enough to know Him as gracious, loving, and merciful. And so, he cries out to God to show unfailing love and abundant mercy by blotting out his transgressions. Transgressions indicate a revolt against God. By violating God's commandments against adultery and murder, David had rebelled against God, and he knew only God's grace, love, and abundant mercy could erase his sin.In Old Testament times, when crimes and debts were forgiven or paid, they were blotted out—erased—from the book in which they were written. When God forgives sin, He similarly blots it out. The apostle Peter urged a crowd that had gathered in Solomon's Portico to repent "that your sins may be blotted out" (Acts 3:19). Micah 7:19 assures us that our pardoning God casts all our sins into the depths of the sea.