Psalm 51: 6-10
We all make mistakes. Psalm 51 is David's prayer in response to the biggest mistake of his life. Through this passage we discover the keys to finding peace with these mistakes. The whole episode with David and Bathsheba should never have happened, but as the mistakes compounded to basically end in murder and death of a baby, David stayed true to God, dealt with the mistakes, and continues to be revered as "a man after God's heart" even today.
On multiple occasions with the disciples were filled with fear and dread, Jesus came to them with a greeting of "peace" before anything else. If we can find Jesus in this hectic, distracted world, then we too will find "peace."