by the singing; "through the children of Israel coming near to the sanctuary," these being the Israelites. A Midrash noted that says, "from 25 years old and upward they shall go in to perform the service in the work of the tent of meeting," while , 23, 30, 35, 39, 43, and 47 say that Levites "30 years old and upward" did service in the tent of meeting. The Midrash deduced that the difference teaches that all those five years, from the age of 25 to the age of 30, Levites served apprenticeships, and from that time onward they were allowed to draw near to do service. The Midrash concluded that a Levite could not enter the Temple courtyard to do service unless he had served an apprenticeship of five years. And the Midrash inferred from this that students who see no sign of success in their studies within a period of five years will never see any. Rabbi Jose said that students had to see success within three years, basing his position on the words "that they should be nourished three years" in . The Mishnah taught that a disability that did not disqualify priests disqualified Levites, and a disability that did not disqualify Levites disqualified priests. The Gemara explained that our Rabbis taught that disqualified priests by reason of a bodily blemish, and not by reason of age; and Levites were disqualified by age, for they were qualified for service only from the age of 30 to 50, and not by bodily blemish. It follows, therefore, that the disability that does not disqualify priests disqualifies Levites, and the disability that does not disqualify Levites disqualifies priests. The Gemara taught that we know this from a Baraita in which our Rabbis noted that says: "This is that which pertains to the Levites." From , "And from the age of 50 years they shall return from the service of the work," we know that Levites were disqualified by age. One might have argued that they were disqualified by bodily blemish too; thus, if priests who were not disqualified by age were nevertheless disqualified by bodily blemish, Levites who were disqualified by age should surely have been disqualified by bodily blemish. therefore says: "This is that which pertains to the Levites," to instruct that "this," that is, age, only disqualifies Levites, but nothing else disqualifies them. One might also have argued