A lion may come to be beholden to a mouse

There are times when the weak can help the strong. A rich or eminent man should treat a poor or obscure man with consideration, for one day he may be beholden to him – that is, indebted to him – for doing him a great service.

It is the story of the lion in the fable who spared the life of a mouse and was later rewarded by the mouse, who gnawed through the net in which the lion had been trapped.