“And the Lord God made for Adam and for his wife garments of skins and clothed them.”
Genesis 3:21 ESV
The animal sacrifices established in Leviticus institutionalized the principle found in this verse where we see God sacrificing an animal and using the skins to cover Adam & Eve. The sacrifice of animals of the Mosaic covenant were established to cover the sins of the Israelites. Christ fulfills this covenant on the cross, becoming the sacrificial lamb, the blood atonement, for humanities sins, once and for all. The arc has been completed from the first Adam to Christ, the last Adam.