Just as the clouds appear before the rain, thus Muhammad (peace be upon him) had some indications before hand of the things to come. He had frequent dreams, in some dreams he saw himself flying to the heavens in the great void of space. In some dreams he saw the stars bow to him. In some dreams he heard the trees, the rocks and the ether inanimate objects calling to him. In some dreams he saw himself standing at the summit of a mountain, and calling to the people assembled below in the valley. These dreams foretelling of some great things to come motivated Muhammad (peace be on him) to contemplate and meditate. To seek enlightenment through contemplation and meditation, Muhammad (peace be on him) sought the solitude of a cave in Mount Hira, some distance away from the city of Makkah. Muhammad (peace be on him) spent long hours in the cave absorbed in thought and meditation. When the stay in the cave extended to a long time Ali brought food for Muhammad in the cave. Ali kept watch on the cave and patrolled the neighborhood. One day in the year 611, the angel Gabriel appeared in the cave, and gave Muhammad (peace be on him) the tidings that God had commissioned him as a prophet and charged him to communicate the message of God to the people. The visitation of the angel, an unusual occurrence was a novel experience which upset Muhammad (peace be on him) and made him highly nervous.