What does Genesis 31:39 mean?

Jacob is finally expressing all of his frustration to Laban, laying out exactly how his father-in-law has mistreated him for the last twenty years. Jacob's point is that he is the one who has been cheated by Laban, not the other way around. In fact, Jacob is insisting, he has always operated above reproach as Laban's servant. In the previous verse, he said he never took any of the full-grown rams as food for himself. Now he says that he even had to cover the loss of sheep and goats killed by predators, sparing Laban from that expense.

Apparently, it was common in this era for shepherds to be protected from the theft or destruction of animals in their care, especially if those animals were killed at night. In Jacob's case, however, Laban never paid for any of those losses. Even though Laban was a fraud (Genesis 29:20–28), and a cheat (Genesis 30:31–36), Jacob had served him with integrity far above and beyond what was owed.