Reland, de Relig. Moham. l. i. p. 17 - 47. Sale's Preliminary Discourse, p. 73 - 76. Voyage de Chardin, tom. iv. p. 28 - 37, and 37 - 47, for the Persian addition, "Ali is the vicar of God!" Yet the precise number of the prophets is not an article of faith.