His offering be of the flocks - See Clarke on Leviticus 1:2 (note).

of the flocks

Leviticus 1:2 Speak to the children of Israel, and say to them, If any man of you bring an offering to the LORD...

Genesis 4:4 And Abel, he also brought of the firstborn of his flock and of the fat thereof. And the LORD had respect to Abel and to his offering:

Genesis 8:20 And Noah built an altar to the LORD; and took of every clean beast, and of every clean fowl, and offered burnt offerings on the altar.

Isaiah 53:6,7 All we like sheep have gone astray; we have turned every one to his own way; and the LORD has laid on him the iniquity of us all...

John 1:29 The next day John sees Jesus coming to him, and said, Behold the Lamb of God, which takes away the sin of the world.

a burnt sacrifice. Olah, a burnt offering, from alah, to ascend, because this offering ascended, as it were, to God in flame and smoke, being wholly consumed; for which reason its is called in the Septuagint, [], a whole burnt offering. This was the most important of all the sacrifices; and no part of it was eaten either by the priest or the offerer, but the whole was offered to God. It has been sufficiently shown by learned men, that almost every nation of the earth, in every age, had their burnt offerings, from the persuasion that there was no other way to appease the incensed gods; and they even offered human sacrifices, because they imagined that life was necessary to redeem life, and that the gods would be satisfied with nothing less.

a male

Leviticus 1:3 If his offering be a burnt sacrifice of the herd, let him offer a male without blemish...

Leviticus 4:23 Or if his sin, wherein he has sinned, come to his knowledge; he shall bring his offering, a kid of the goats, a male without blemish:

Leviticus 22:19 You shall offer at your own will a male without blemish, of the beeves, of the sheep, or of the goats.

Malachi 1:14 But cursed be the deceiver, which has in his flock a male, and vows, and sacrifices to the LORD a corrupt thing: for I am a great King...

Influences that Gave Rise to the Priestly Laws and Histories
[Sidenote: Influences in the exile that produced written ceremonial laws] The Babylonian exile gave a great opportunity and incentive to the further development of written law. While the temple stood, the ceremonial rites and customs received constant illustration, and were transmitted directly from father to son in the priestly families. Hence, there was little need of writing them down. But when most of the priests were carried captive to Babylonia, as in 597 B.C., and ten years later the temple …
Charles Foster Kent—The Origin & Permanent Value of the Old Testament