Adam and Eve became aware of their nakedness after they had sinned. They tried to hide their nakedness by making aprons using fig leaves. Man can never hide his sinful nature from God. All of man’s efforts are but futile attempts to cover hide his true nature. It was at this time that God provided garments of skin to cover the nakedness of Adam and Eve. This was the permanent solution not only for the remedy of nakedness before God but also for sin. An innocent animal had to die in order to provide garments for man.
This was God’s plan to provide for the covering of sins. Provision was made in eternity past that in due time a lamb will be sacrificed to provide the final solution to deal with sin. That lamb was Jesus Christ. Jesus by His sacrificial death opened a new and living way to approach God. (John 3:16) "For God so loved the world that He gave His only-begotten Son, that whoever believes in Him should not perish but have everlasting life."
Thus, a sinful man is washed in the blood of Jesus when he believes on Him. Spiritually speaking, man is given a change of clothing. Just as God replaced Adam and Eve’s garments, today God covers us with the robe of righteousness. Our filthy garments of sin are removed forever. The righteousness of Jesus covers us. Thus putting on Christ is putting on the robe of righteousness. Thus, our ugliness of sin is covered. We can stand before God. We cannot now contemplate on committing sin and fulfil the desires of the flesh as we did before.