Matthew Poole and continuators on Leviticus 3:1

1 AND if his oblation be a sacrifice of peace-offering , if he offer it of the herd, whether it be a male or female , he shall offer it without blemish, before the LORD.

Which was an offering for peace and prosperity and the favour and blessing of God, either 1. obtained, and so this was a thank-offering, as Levit. 7. 12, 16. or 2. desired▪ and so it was a kind of supplication to God▪ as Iudg. 20. 26. 1 Chron. 21. 26.

Which were allowed here▪ though not in burnt-offerings, because those principally respected the honour of God, who is to be served with the best▪ but the peace-offerings did primarily respect the benefit of the offerer, and therefore the choice was left to himself.