"O Messenger, announce that which has been revealed to you from your Lord" [up to] the end of the verse.

Yahya [narrated] from Abu Umayyah, from al-Hasan, that the Messenger of Allah (peace be upon him) complained to his Lord about his people, saying: 'O Lord, my people have frightened me, so grant me a sign from You so that I may know that there is no fear upon me.' Allah revealed to him to go to such-and-such a valley, in which there was such-and-such a tree, and [to summon] a branch from it so that it might come to him. He went to the valley and summoned a branch from it; it came, furrowing the ground, until it stood upright before him. He kept it for as long as Allah willed him to keep it, then he said: 'Return as you came.' It returned. The Messenger of Allah said: 'I know now, O Lord, that there is no fear upon me.'