Leviticus 4:1

‘And Yahweh spoke to Moses, saying,'

This is, as ever, the indication of the introduction of a new section, possibly communicated at a different time from the earlier one. But it confirms that the purification for sin offering was communicated by God to Moses on its own at a particular point in time, although then being brought within the general pattern of offerings. These were to be seen as the words of Yahweh (see Numbers 7:89). This section goes on to Leviticus 5:13.