This Sura, which Nöldeke places last, and Muir sixth, in the earliest class of Meccan Suras, must at least have been composed prior to Sura xxxvii. 182, where it is quoted, and to Sura xv. 87, which refers to it. And it can scarcely be an accidental circumstance that the words of the first, second, and fifth verses do not occur in any other Suras of the first Meccan period as given by Nöldeke, but frequently in those of the second, which it therefore, in Nöldeke, opinion, immediately precedes. But this may be accounted for by its having been recast for the purposes of private and public devotion by Muhammad himself, which is the meaning probably of the Muhammadan tradition that it was revealed twice. It should also be observed that, including the auspicatory formula, there are the same number of petitions in this Sura as in the Lord's Prayer. It is recited several times in each of the five daily prayers, and on many other occassions, as in concluding a bargain, etc. It is termed "the Opening of the Book," "the Completion," "the Sufficing Sura," the Sura of Praise, Thanks, and Prayer," "the Healer," "the Remedy," "the Basis," "the Treasure," "the Mother of the Book," "the Seven Verses of Repetition." The Muhammadans always say "Amen" after this prayer, Muhammad having been instructed, says the Sonna, to do so by the Angel Gabriel.