‘And to the children of Israel you will speak, saying, “Take a he-goat for a purification for sin offering, and a calf and a lamb, both a year old, without blemish, for a whole burnt offering, and an ox and a ram for peace offerings, to sacrifice before Yahweh, and a grain offering mingled with oil, for today Yahweh appears to you.'
Having offered for himself he can then offer for the people, ‘the children of Israel'. For the people the offerings are to be a he-goat for the purification for sin offering, a year old calf and lamb for a whole burnt offering, and a bull ox and a ram for peace sacrifices, together with a grain offering mingled with oil. And being on behalf of the whole people they are male.
Again there is a lowering in level of the offerings. This may be because again the people have not yet had time to ‘sin' to any extent since the consecration of the priests has taken place and the new way of worship has been introduced, so that instead of a bull ox for a purification for sin offering for the people (Leviticus 4:14), there is a he-goat. But it may also be because this was the people's offering excluding the priests, while that for the ‘whole congregation of Israel' (Leviticus 4:13) was seen as including the priest (see on Leviticus 10:16-20)
For the whole burnt offering there was here a calf and a lamb. This was probably in order to indicate that their new status and need for atonement was in its infancy. But it was also because the lamb was also for the morning sacrifice, for the regular morning and evening sacrifices were to be of a similar lamb (Exodus 29:38).
The third group of offerings was to be of a bull ox and a ram for their peace sacrifice. Here they would be partaken of and represented Israel's present well being and position of peace with God which was full developed. Thus the constituents are carefully selected.