Let positive, strong, helpful thoughts enter into your brains from very childhood. Lay yourselves open to these thoughts, and not to weakening and paralysing ones.
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.
So sometimes things are ahead and sometimes they are behind; Sometimes breathing is hard, sometimes it comes easily; Sometimes there is strength and sometimes weakness; Sometimes one is up and sometimes down. Therefore the sage avoids extremes, excesses, and complacency.