"Unto Adam also and to his wife did the LORD God make coats of skins, and clothed them." (Genesis 3:21)
This action by the Lord is very significant. God Himself apparently sacrificed some of His animal creation (possibly two innocent and blemish-free sheep) in order to provide clothing for the first man and woman. In the first place, this tells us that clothing is important in God's plan for human beings; nudity became shameful once sin entered the world.
In the second place, we learn that symbolically speaking, clothing must be provided by God Himself. Man-made "aprons" of fig leaves will not suffice, as they represent human works of righteousness which can never make us presentable to God: ". . . we are all as an unclean thing, and all our righteousnesses are as filthy rags" (Isaiah 64:6). However, God has sacrificed His own "Lamb of God" (John 1:29), pure and spotless, yet also willing to die for us. Thereby ". . . he hath clothed me with the garments of salvation, he hath covered me with the robe of righteousness" (Isaiah 61:10), fashioned from the perfect righteousness of the Lamb.
But in order to do this, the innocent blood of the sacrifice must be shed, for "the life of the flesh is in the blood" (Leviticus 17:11). When sin entered the world, there also came "death by sin" (Romans 5:12), and "without shedding of |innocent| blood is no remission |of sin|" (Hebrews 9:22).
How much of this could have been comprehended by Adam and Eve as they watched God slay their animal friends so that they once again could walk with God we do not know, but it changed their lives. Just so, when we really see "the precious blood of Christ" (1 Peter 1:19) spilled in sacrifice for our redemption, our lives also are forever changed. He hath covered me with the righteousness of Christ. HMM