Man proposes; God disposes, says an old adage. It does not mean that God is perpetually opposing whatever man does. What really happens is that when man exerts through his egoism in a manner which violates the eternal law of God, he naturally feels frustrated, being beaten back by the law of Truth.
He who knows, knows not; he who knows not, knows. This is a statement in the Upanishad, meaning that one who has realised the Truth has no personality-consciousness, and one who has it knows not the Truth.
The four noble truths of the Buddha that there is suffering, that there is a cause for suffering, that there is a way out of suffering and that there is a state beyond suffering are proof enough to show that he was not a nihilist in the sense in which the word is used today, but a practical man who had an eye to doing something than merely conjecturing about Truth and its realisation.