In the tabernacle of the congregation without the vail, which is before the testimony, Aaron and his sons shall order it from evening to morning before the LORD: it shall be a statute for ever unto their generations on the behalf of the children of Israel.
Aaron and his sons - were to take charge of lighting it in all time coming. 'It is clear that these regulations refer only to Aaron and his sons, who acted as priests in the time of Moses. As they stand here, they could not bear an immediate reference to the later temple service, but could be referred to it only by means of an accommodating interpretation, which would also require to define more exactly how much of this was applicable to the high priest, and how much to the other priests; for neither of these points is here distinctly defined' (Bleek, quoted by Havernick, 'Introduction to the Pentateuch,' p. 290).
Shall order it from evening to morning. The tabernacle having no windows, the lamps required to be lighted during the day. Josephus says that in his time only three were lighted; but his were degenerate times, and there is no Scripture authority for this limitation. But although the priests were obliged from necessity to light them by day, they might have let them go out at night, had it not been for this express ordinance.
It shall be a statute for ever. This expression, which occurs very frequently in the Mosaic books (Exodus 30:21; Leviticus 3:17; Leviticus 6:8; Leviticus 7:36; Leviticus 10:9; Leviticus 17:7; Leviticus 23:14; Leviticus 23:21; Leviticus 23:31; Leviticus 23:41), is not to be taken literally, as denoting a permanently fixed irrevocable law, but only an ordinance which was designed to continue in force until the course of time should require it to be modified or abrogated.