His achievement as religious reformer rests largely upon the state of preparation in which he found his medium, but it owes its efficiency to one force alone. Mahomet was possessed of one central idea, the indivisibility of God, and it was sufficient to uphold him against all calamities. The Kuran sounds the note of insistence which rings the clarion call of his message. With eloquence of mind and soul, with a repetition that is wearisome to the outsider, he forces that dominant truth into the hearts of his hearers. It cannot escape them, for he will not cease to remind them of their doom if they do not obey. What he set out to do for the religious life of Arabia he accomplished, chiefly because he concentrated the whole of his demands into one formula, "There is no God but God"; then when success had shown him the measure of his ascendancy, "There is no God but God, and Mahomet is His prophet." At the end of his life idolatry was uprooted from his native country. The tribes might rebel against the heaviness of his political yoke, and were often held to him by the slenderest of diplomatic threads, but their monotheistic beliefs remained intact once Islam had gained the ascendancy over them. At the end of the Farewell Pilgrimage, he realised with one grand uplifting of his soul in thanksgiving that he had indeed caught up the errant attempts of Arabia to remodel its unsatisfying faith, and had made of them a triumphant reality, in which the conception of Allah's unity was the essential belief. Besides his religious and political attainments, he gave to Arabia as a whole its first written social and moral code. Here the estimate of his accomplishment is difficult to render, bemuse comparison with the existing state is almost impossible. Extensively in the Kuran, but to a greater degree in the mass of his traditional sayings, crystallised into a standard edition by Al-Bokhari, when due allowance has been made for the additions and exaggerations of his followers, the chief characteristic is the casual nature of his laws.