They then continued to ask other questions which throw a curious light on the kind of problems which interested the Muslims of the day, or which could be thought as deserving of attention. Why have men ten fingers and ten toes?—why are four fingers on each hand divided into three phalanges, whilst the thumbs have only two each?—why has the face seven openings?—why are there twelve dorsal vertebrae and seven cervical vertebrae? etc., constantly suggesting some mystic meaning as lying under particular numbers. They cited “on earth are signs of men of firm belief, and also in your own selves; will ye not then consider them?” (Qur., 51, 20-21): “God setteth forth these similitudes to men that haply they may reflect” (Qur., 14, 30), and “we will shew them our signs in (different) countries and among themselves, until it become plain to them that it is the truth.” These suggestions produced doubt in the minds of many hearers, and gave the impression that the missionary had thought more deeply on the problems of religion than the ordinary teachers; and so the hearers were induced to ask the _daʿi_ to instruct them and reveal the answers to some of the problems he proposed. Forthwith he would begin a discourse dealing with some of these questions, and then suddenly check himself: the religion of God is too precious to be disclosed to those who are not worthy and who may, perhaps, treat it with contempt: God has always required a pledge of those to whom he has disclosed his mysteries. Thus we read, “And remember that we have entered into covenant with the prophets and with thee, and with Noah, and Abraham, and Moses, and Jesus the son of Mary; and we formed with them a strict covenant” (Qur., 33, 7), and again “some there were among the faithful who made good what they had promised to God” (id., 23),—“O believers, be faithful to your engagements” (Qur., 5, 1),—“be faithful in the covenant of God when ye have covenanted, and break not your oaths after ye have pledged them: for now ye have made God to stand surety for you” (Qur., 16, 93), and many similar passages. “So now,” the _daʿi_ said, “pledge yourself, putting your right hand in mine, and promise me with the most inviolable oaths and assurances that you will not betray our secret, that you will assist no-one against us, that you are laying no snare for us, that you will use the truth only in speaking with us, and that you will not join any of our enemies against us.” By this means they discovered how far the would-be proselyte was ready to be submissive and obedient, and accustomed him to act in absolute conformity with his superiors. If the proselyte readily took this pledge, the missionary next said, “Give us now an offering from your goods and first fruits which shall be a preliminary to the disclosure which we are about to make to you of our doctrine, and a pledge which you will give for it.” By this they tested how far the