Animal sacrifices were instituted as early as Genesis 3:21
Up to the time of Leviticus burnt offerings, which were totally consumed nothing but ashes left, were made by the faithful who wanted to approach God.
The act of making offerings was awful, horrific, and shocking just as sin is, and meant to reveal and remind us of how God feels about sin.
Animals used in the burnt offering had to be male, without blemish, and not carnivores (cattle or sheep) to typify Jesus.
Burnt offerings point to God’s satisfaction with Jesus Christ’s willingness to die to purchase us from sin.
God abhors sin, and provides the remedy.