Every attempt that Adam and Eve made to cover up their sin left them exposed before God. Making clothes of fig leaves didn’t cover their shame. Hiding in the trees didn’t avoid the all-seeing eye of the Judge. Passing the blame onto another didn’t relieve them of their personal guilt and responsibility to obey God. The only solution to sin was for God to provide His own sacrifice through the shedding of innocent blood on their behalf.
So Adam and Eve, stripped of all self-effort and works, were covered by the Lord. He killed an innocent animal from the Garden, shed its blood and the made for Adam and Eve tunics of skin, and clothed them (Genesis 3:21).
From Eden onward, there have been two competing religions in the world. The first is packaged in many different names and varieties of self-effort at being good and godly. Each of these comes down to man attempting to reach God by personal effort. That effort may come in the form of saying a prayer, denying self of some necessity or desire, helping others through social causes, or participating in a religious ritual.
Christianity, however, is based upon faith in God’s provision. Man has no part in reaching God, but God reached down to us. We don’t seek after Him, He came to seek and to save the lost. We don’t sacrifice and surrender, God the Father gave His Son to die for the sinful. God, by grace, saves those who have faith in His provision. Biblical religion condemns the addition of any of our own works to gain God’s favor or earn His forgiveness. Our self-efforts nullify grace and make Christ’s death in vain.
No man is justified by the works of the law but by faith in Jesus Christ (Galatians 2:16)