Numbers 3:40

40 And the Lord spoke to Moses, saying, Count every first-born male of the children of Israel from a month old and upwards, and take the number by name.

Numbers 3:40 In-Context

38 They that encamp before the tabernacle of witness on the east Moses and Aaron and his sons, keeping the charges of the sanctuary according to the charges of the children of Israel; and the stranger that touches them, shall die.
39 All the numbering of the Levites, whom Moses and Aaron numbered by the word of the Lord, according to their families, every male from a month old and upwards, two and twenty thousand.
40 And the Lord spoke to Moses, saying, Count every first-born male of the children of Israel from a month old and upwards, and take the number by name.
41 And thou shalt take the Levites for me—I the Lord—instead of all the first-born of the sons of Israel, and the cattle of the Levites instead of all the first-born among the cattle of the children of Israel.
42 And Moses counted, as the Lord commanded him, every first-born among the children of Israel.

The Brenton translation of the Septuagint is in the public domain.