Albert Barnes Commentary Leviticus 1:10

"And if his oblation be of the flock, of the sheep, or of the goats, for a burnt-offering; he shall offer it a male without blemish." — Leviticus 1:10 (ASV)

Of the flocks - These directions are more brief than those for the bullock. The burnt-offering of the sheep must have been that with which the people were most familiar in the daily morning and evening service (Exodus 29:38–42). Sheep were preferred for sacrifice when they could be obtained, except in some special sin-offerings in which goats were required (Leviticus 4:23; Leviticus 9:3; Leviticus 16:5). The lamb “without blemish” is a well-known type of Christ (Hebrews 9:14; 1 Peter 1:19).