In the village of Sarnath, a suburb of Benares, Buddha encountered his companions in asceticism. At first, they didn't want to have anything to do with him and resolved to ignore him. As Buddha approached, however, they felt an extraordinary presence and spontaneously rose to greet him. They were so awed by his presence that they asked him to explain what had happened. Buddha Shakyamuni started with the existence of suffering and explained what he now knew.
For Buddha, the circumstance of the moment was this chance meeting with his former companions. All of them had been motivated originally by the question of suffering, so he gave his first teaching, the four noble truths.