Is any man’s blood fit to redeem him, seeing that it was Christ who shed his blood for the redemption of all? Is anyone’s blood comparable to Christ’s? Is anyone great enough to make atonement for himself over and above the atonement which Christ has offered in himself, Christ who alone has reconciled the world to God by his blood? What greater victim, what more excellent sacrifice, what better advocate can there be than he who became the propitiation for the sins of all, and gave his life for us as our redemption? We do not need, then, to look for an atonement or redemption made by each individual, because the price paid for all is the blood of Christ, that blood by which the Lord Jesus has redeemed us, he who alone has reconciled us to the Father. He has labored even to the end, shouldering our burdens himself. Come to me, he says, all you that labor, and I will refresh you.
From The Explanation of the Psalms by Saint Ambrose, bishop