For thus we learned, etc.: For thus we learned, that it is written: "And these are the names of the sons of Aaron, the priests, etc.." And it is written: "The firstborn Nadab and Abihu, Eleazar and Ithamar." It is asked: Why does it say "Eleazar and Ithamar" instead of just saying "and Eleazar and Ithamar," as it says "and Abihu"? Why is the conjunction "and" missing in Eleazar? And it is answered: But Abihu was equivalent to his two brothers together. And the meaning of the verse is: "And Abihu" is like "Eleazar and Ithamar." And Nadab was equivalent to all of them together.