His exaltation upon the mountain of light soon faded into uncertainty and fearfulness before the influence of the world's harsh wisdom. Mahomet entered upon a period of hesitation and dreariness, doubtful of himself, of his vision, and of the divine favour. His soul voyaged on dark and troubled seas and gazed into abysmal spaces. At one time he would receive the light of the seven Heavens within his mind, and feel upon him the fervour of the Hebrew prophets of old, and again he would call in vain upon God, and, and seeking, would be flung back upon a darkness of doubt more terrible than the lightnings of divine wrath. In all those exaltations and glooms Khadijah had part; she comforted his distress and shared his elation until the sorrowful period of the Fattrah, the pause in the revelation, was past. The period is variously estimated by the chroniclers, and there are many nebulous and spurious legends attaching to it, but whatever its length it seems certain that Mahomet gained within it a fuller knowledge of Jewish and Christian tenets, probably through Zeid, the Christian slave in his household, and most accounts agree that the Fattrah was ended by the revelation of the sura entitled "The Enwrapped," the mandate of the angel Gabriel: "O thou enwrapped in thy mantle, Arise and warn!" The explanation of the term "enwrapped in thy mantle" shows the prevailing belief in good and evil spirits characteristic of Mahomet's time. Wandering on the mountain, he saw in a vision the angel Gabriel seated on a throne between heaven and earth, and afraid before so much glory, ran to Khadijah, beseeching her to cover him with his mantle that the evil spirits whom he felt so near him might be avoided. Thereupon Gabriel came down to earth and revealed the Sura of Admonition. This supernatural command would appear to be the translation into the imaginative world of the peace of mind that descended upon Mahomet, and the conviction as to the reality of his inspiration following on a time of despair. The command fell to one who was peculiarly fitted by nature and circumstance to obey it effectively. To Mahomet, who knew somewhat the chaos of religions around him--Pagan, Jewish, and Christian struggling together in unholy strife--the conception of God's unity, once it attained the strength of a conviction, necessarily resolved itself into an admonitory mission. "There is no God but God," therefore all who believe otherwise have incurred His wrath; hasten then to warn men of their sins. So his conviction passed out of the region of thought into action and received upon it the stamp of time and place, becoming thereby inevitably more circumscribed and intense.