a new ability?

A pretty sweet idea, one thing ive come to remember is that most paladins in lore are of a very good...Holy alignment. So for every monster that is evil compared to pallys (which is like everything), have an ability that takes some of our own HP's and turns it into a DD on the enemy. We have act of valor that takes all of our own HP's and gives them to another PC, why not an ability that gives Part of our HP (not all but some {probably a small portion} ) and hit a mob with it. Making Act of Valor a prerequisite for it.