It is weakness, says the Vedanta, which is the cause of all misery in this world. Weakness is the one cause of suffering. We become miserable because we are weak. We lie, steal, kill and commit other crimes, because we are weak. We die because we are weak. Where there is nothing to weaken us, there is no death nor sorrow. We are miserable through delusion. Give up the delusion and the whole thing vanishes.
Say to your own minds, "I am He, I am He". Let it ring day and night in your minds like a song, and at the point of death declare : "I am He". That is truth; the infinite strength of the world is yours.