This can be stated in active form. Alternate translation: "God showed me mercy" or "I obtained mercy from God" (See: [[rc://en/ta/man/jit/figs-activepassive]])
"the chief sinner" or "the worst sinner." Paul is saying that he has sinned more than any other sinner, not that he has been the leader of a group of sinners. See how you translated this in [1 Timothy 1:15](../01//15.md).