And with their friend and guide remained Abu Bekr and Ali--Abu Bekr because he would not leave his companion in prayer and persecution, and Ali because his valour and enthusiasm made him a protector against possible attacks. Here was the opportunity for the Kureisch. They knew the extent of the emigration, and that Abu Bekr and Ali were the only Muslim of importance left except the Prophet. They determined to make one last attempt to coerce into submission this fantastic but resolute leader, who possessed in supreme measure the power of winning the faith and devotion of men. Tradition has it that Mahomet's assassination was definitely planned, and Mahomet assuredly thought so too, when he discovered that a man from each tribe had been chosen to visit his home at night. The motive can hardly have been assassination, but doubtless the chiefs were prepared to take rather strong measures to restrain Mahomet, and this action finally decided the Prophet that delay was dangerous. At this crisis in his fortunes he had two staunch helpers, who did not hesitate to risk their lives in his service, and with them he anticipated his foes. Ali was chosen to represent his beloved master before the menaces of the Kureisch. Mahomet put him into his own bed and arrayed him in his sacred green mantle; then, as legend has it, taking a handful of dust, he recited the sura "Ya Sin," which he himself reverenced as "the heart of the Kuran," and scattering the dust abroad, he called down confusion upon the heads of the Unbelievers. With Abu Bekr he then fled swiftly and silently from the city and made his way unseen to the cave of Thaur, a few miles outside its boundaries. Around the cave of Thaur cluster as many and as beautiful legends as surround the stable at Bethlehem. The wild pigeons flew out and in unharmed, screening the Prophet by their untroubled presence from the searchings of the Kureisch, and a thorn tree spread her branches across the mouth of the cave supporting a spider's frail and glistening web, which was renewed whenever a friend visited the two prisoners to bring food and tidings. Here Mahomet and Abu Bekr, henceforward known as the "Second of Two," remained until the fierceness of the pursuit slackened. Asma, Abu Bekr's daughter, brought them food at sundown, and what news she could glean from the rumours that were abroad, and from the lips of Ali. There was very real danger of their surprise and capture, but once more Mahomet's magnificent faith in God and his cause never wavered. Abu Bekr was afraid for his master: "We are but two, and if the Kureisch find us unarmed, what chance have we?" "We are but two," replied Mahomet, "but God is in the midst a third."