Answer:
Even the small can help the strong, show mercy to others, and help others and they will help you.
Step-by-step explanation:
If the answer was "Leave sleeping lions alone", we would never had had a story. It may be a good message to the mouse, but then the lion would not have been given the help he also needed.
Get revenge when you can is definitely not the moral of the story, it is actually the complete opposite.