As Sirach chooses how to summarize the life of King David, he mentions some things that would be mentioned in any history: killing Goliath with a stone, the defeat of the Philistines, and the many songs and prayers he wrote. In a modern history, just as in the actual record we have from the books of Samuel and Chronicles, his sins would play a larger part though. The only thing that Sirach has to say about his sins is that the Lord forgave him.
Perhaps Sirach’s account is too rosy for a man who committed adultery, murdered loyal servant, and forgot his role as a steward of God's people. The original account is harsher too concerning David's war against the Philistines. By Sirach's description it was all glory, but God would not let David build his temple since his hands had shed too much blood. By Sirach's account, David is a hero.
But David is a hero. He did kill Goliath when the Philistines threatened to destroy Israel. He did establish Israel as a kingdom. He was not perfect, not by any means, but then no one in the Bible is except Jesus and his mother. Noah was a drunk. Abraham was a cowardly liar. Moses was a murderer. In other words, they were just like us. What is remarkable about them was not that they never did anything wrong, but that they did something right. Modern histories may dwell on the dark valleys of a life, but there is something to be said for the glorious peaks as well.
We could look at David and say, “Well at least I’ve never been as bad as he was”, but then have we ever been as good as he was? Even King Herod liked to listen to John the Baptist, and did not want to kill him. What does it take to judge a human life? Should we consider how good someone has been or how low they have sunk, or simply take an average of a whole life?
This sort of calculation is too much for anyone. We must not think that our good deeds will outweigh our bad ones. We must rely on the mercy of God, that he will forgive us our sins as he forgave the sins of David. The most important fact about David in the first reading today is not that he killed a giant or who he defeated. It is is this: “The LORD forgave him his sins.”