But, meeting such objectors on their own ground, we need not go into the matter further than to refer to the high authority of Dillmann, who declares this theory of the post-exilian origin of this institution to be "absolutely incredible;" and in reply to the objection that the day is not alluded to in the whole Old Testament history, justly adds that this argument from silence would equally forbid us to assign the origin of the ordinance to the days of the return from Babylon, or any of the pre-Christian centuries! for "one would then have to maintain that the festival first arose in the first Christian century; since only out of that age do we first have any explicit testimonies concerning it."[20] [20] "Die Bücher Exodus und Leviticus," 2 Aufl., p. 525. Again, the first verse of the chapter gives as the occasion of the promulgation of this law, "the death of the two sons of Aaron," Nadab and Abihu, "when they drew near before the Lord and died;" a historical note which is perfectly natural if we have here a narrative dating from Mosaic days, but which seems most objectless and unlikely to have been entered, if the law were a late invention of rabbinical forgers. On that occasion it was, as we read (v. 2), that "the Lord said unto Moses, Speak unto Aaron thy brother, that he come not at all times into the holy place within the veil, before the mercy-seat which is upon the ark; that he die not: for I will appear in the cloud upon the mercy-seat." Into this place of Jehovah's most immediate earthly manifestation, even Aaron is to come only once a year, and then only with atoning blood, as hereinafter prescribed.