From the letter to Diognetus
When our wickedness had reached its culmination, it became clear that retribution was at hand in the shape of suffering and death. The time came then for God to make known his kindness and power (how immeasurable is God’s generosity and love!). He did not show hatred for us or reject us or take vengeance; instead, he was patient with us, bore with us, and in compassion took our sins upon himself; he gave his own Son as the price of our redemption, the holy one to redeem the wicked, the sinless one to redeem sinners, the just one to redeem the unjust, the incorruptible one to redeem the corruptible, the immortal one to redeem mortals. For what else could have covered our sins but his sinlessness? Where else could we, wicked and sinful as we were, have found the means of holiness except in the Son of God alone?
How wonderful a transformation, how mysterious a design, how inconceivable a blessing! The wickedness of the many is covered up in the holy One, and the holiness of One sanctifies many sinners.