Every mistake is a lesson learnt.

les·son (lsn)
n.
1. Something to be learned: lessons from observing nature.
2. A period of instruction; a class.
3. An assignment or exercise in which something is to be learned.
4. The act or an instance of instructing; teaching.
5. An experience, example, or observation that imparts beneficial new knowledge or wisdom.
6. The knowledge or wisdom so acquired.
7. A rebuke or reprimand.
8. often Lesson A reading from the Bible or other sacred text as part of a religious service.