Genesis 3:21

God made coats of skins - It is very likely that the skins out of which their clothing was made were taken off animals whose blood had been poured out as a sin-offering to God; for as we find Cain and Abel offering sacrifices to God, we may fairly presume that God had given them instructions on this head; nor is it likely that the notion of a sacrifice could have ever occurred to the mind of man without an express revelation from God. Hence we may safely infer, 1. That as Adam and Eve needed this clothing as soon as they fell, and death had not as yet made any ravages in the animal world, it is most likely that the skins were taken off victims offered under the direction of God himself, and in faith of Him who, in the fullness of time, was to make an atonement by his death. And it seems reasonable also that this matter should be brought about in such a way that Satan and death should have no triumph, when the very first death that took place in the world was an emblem and type of that death which should conquer Satan, destroy his empire, reconcile God to man, convert man to God, sanctify human nature, and prepare it for heaven.