Towards the end of his life, King David seriously offended God by conducting a detailed census of Israel’s potential army. Almost as soon as the census was complete, David realised his error: he had failed to trust God, trusting - instead - the strength of his military force. God took action to discipline the ageing king, and demanded that David choose from three proposed punishments. David made his choice immediately. He opted for the third, three days of plague, stating: “Let’s fall into the hand of God, for his mercy is great; but let me not fall into human hands.”
Even though David’s trust in God had evidently become somewhat flakey, he was quick to trust God’s discipline. He did not think of God as being terribly vengeful, but as being essentially merciful. One of the features of David's story is that he was evidently an experienced sinner, and as such, understood more than many people the depths of God’s mercy. If he was going to be punished, David had no doubt that he wanted to be punished by God.
It is when we entrust God with our failures and our disasters that we begin to experience the depth of his mercy. And it is as we begin to experience the depth of God’s mercy that we learn how to show mercy to others.