Adam and Eve had been tempted and succumbed to the temptation.  God calls that sin.  They had sinned and their nakedness was exposed.

Whenever you sin, you expose your nakedness and your need to be covered.  Only God’s provision through His Son’s sacrifice can adequately cover you.
Your sin and mine is against God and requires a sacrifice…a blood sacrifice.  These are God’s requirements.

In God’s mercy and grace (the free gift of God to anyone who will receive His Son as Savior) He has done at least the following and more:
1-     God said that if Adam and Eve sinned, death would be the penalty.
2-     God promised Messiah immediately after the sin against Him (See Genesis 3:15)
3-     God pronounced the consequences for everyone involved in the sin. (The serpent would eat dust – a symbol of death; Eve would have pain in child-bearing and be under the protection and authority of her husband; the ground was under a curse because of Adam.  All the days of Adam’s life he would toil in order to eat and need to fight thorns and thistles, his sweat would be a part of his toil and he would return to the dust of the ground when he died.)
4-     God provided a covering for their nakedness after their sin; many believe that a sacrificial animal’s skin was used to cover them.
5-     God’s word was fulfilled when death became a part of the human experience.

Whenever followers of Christ sin – a type of death occurs.  Our relationship with God is affected, even interrupted.  The Holy Spirit (the Holy Ghost) is grieved until forgiveness is asked of God.  If the followers of Christ ignore our need to confess our sin(s) to God then we can even quench the Holy Spirit within (the Holy Spirit is given to all followers of Christ).

Have you built up a wall of resistance by not confessing your sins to the living God?

(NASB) Genesis 3:21 “The LORD God made garments of skin for Adam and his wife, and clothed them.”

Is God’s covering clothing you?  Only through Christ can anyone be clothed in God’s presence.