'This is a revelation from the most Merciful: a book whereof the verses are distinctly explained, an Arabic Korân, {51} for the instruction of people who understand.... It is revealed unto me that your God is one God.... This is the disposition of the mighty, the wise God. If the Meccans withdraw from these instructions, say, I denounce unto you a sudden destruction.... The unbelievers say, Hearken not unto this Korân; but use vain discourse during the reading thereof, that ye may overcome the voice of the reader by your scoffs and laughter. Wherefore we will surely cause the unbelievers to taste a grievous punishment.... This shall be the reward of the enemies of God, namely, hell fire; therein is prepared for them an everlasting abode, as a reward for that they have wittingly rejected our signs.... Say, what think ye? If the Korân be from God, and ye believe not therein, who will lie under a greater error than he who dissenteth widely therefrom? ... Is it not sufficient for thee that thy Lord is witness of all things?' [Sidenote: Conversion of Ali.] Another time we hear him preaching publicly in a different strain: 'I know no man in the land of Arabia who can lay before his kinsfolk a more excellent offer than that which I now make to you. {52} I offer you the happiness of this world, and of that which is to come. God Almighty hath commanded me to call mankind unto Him. Who, therefore, among you will second me in that work, and thereby become my brother, my vice-regent, my Khalifa (successor)?' In the audience that day was his young cousin, Ali, Abu Talib's son, whom Mohammed had adopted shortly after his marriage with Kadijah, and this sermon is said to have been the cause of his conversion. 'I, O Apostle of God, will be thy minister,' he exclaimed; 'I will knock out the teeth, tear out the eyes, rip up the bellies, and cut off the legs of all who shall dare to oppose thee.' Then in the presence of all the assembly the prophet embraced him, exclaiming, 'This is my brother, my deputy, my Khalifa: hear him and obey him.' In such manner did this Peter of Islam receive his commission. [Sidenote: Conversion of Omar.] There is one other story of this time which must be told. Its central figure is that of the man who later on succeeded Abu Bakr as second Caliph, who captured Jerusalem and Alexandria and conquered {53} Persia, and ruled an Empire as wide as that of Rome. He left for ever the stamp of his dauntless spirit upon Islam. He was one of Mohammed's bitterest opponents and was engaged in elaborating a plot upon the Prophet's life, when he heard that his own brother-in-law and sister were secret converts. His wrath was aroused and he proceeded at once to their house. As he drew near he heard the low murmur of reading. 'What sound was that I heard just now?' he demanded in his rage. 'Nothing,' they replied, as many have done before and since. 'Nay,' he said with an oath, 'I hear that ye are renegades.'