Ezra 6:20

Some render, “And the priests were purified; and the Levites, as one man, were all of them pure.” A contrast is drawn between the universal purity of the Levites and the merely general purity of the priests2Ch 29:34;2 Chronicles 30:3, which made it fitting that the former should undertake the slaughter of all the Paschal lambs, even of those which the priests were to consume. In later times the ordinary practice was for each head of a family to kill for himself.