For someone building a stone wall, those stones which can fill no holes have no value.
Be that stone which can mend no holes. Nature has made you just as you are, and uses you as She wills. Take a rest! A stone which can mend no holes does not get stressed when it cannot do what it is not made for. Be who you are.
You have no battle to fight, for what could oppose the will of Nature? The moment you have a problem to be tackled, and an enemy to be faced - you lose. One who fights the empty air is defeated no matter how he fares.