Genesis 3:14, 15, 21
14 And tto give us he LORD God said to the serpent, Because you have done this, you are cursed above all cattle, and above every beast of the field; on your belly shall you go, and dust shall you eat all the days of your life:
15 And I will put enmity between you and the woman, and between your seed and her seed; it shall bruise your head, and you shall bruise his heel.
21 To Adam also and to his wife did the LORD God make coats of skins, and clothed them.
The first death that Adam saw was that of an animal (probably a lamb). Revelation 13:8 refers to Jesus as the Lamb slain from the foundation of the world. As the animal (probably a lamb) was slain to clothe Adam and Eve after they sinned, so Jesus was slain to give us His robe of righteousness because of our sin.
2 Corinthians 5;21
21 For he (God) has made him (Jesus) to be sin for us, who knew no sin; that we might be made the righteousness of God in him.
Jesus became sin for us so we might have His righteousness.