We have seen the ungodly justified, and have considered the great truth that only God can justify any man. We now come a step further and make the inquiry, How can a just God justify guilty men?
Let me give you a bit of personal experience. When I was under conviction of sin, under the hand of the Holy Spirit, I had a clear and sharp sense of the justice of God. Sin, whatever it might be to other people, became to me an intolerable burden. It was not so much that I feared hell, but that I feared sin. I knew myself to be so horribly guilty that I remember feeling that if God did not punish me for sin He should do so. I felt that the Jude of all the earth ought to condemn such sin as mine. I sat on the judgement seat and condemned myself to perish, for I confessed that had I been God I could have done nothing else than send such a guilty creature as I was down to the lowest hell.
All the while, I had on my mind a deep concern for the honor of God’s name and the integrity of His moral government. I felt that it would not satisfy my conscience if I could be forgiven unjustly. The sin I had committed must be punished. But then there was a question of how God could be just and yet justify me who had been so guilty. I asked my heart: “How can He be just and yet the Justifier?” I was worried and wearied with this question; I could see no answer to it. Certainly, I could never have invented an answer which would have satisfied my conscience.
The doctrine of atonement is to my mind one of the surest proofs of the divine inspiration of Holy Scripture. Who would or could have thought the just Ruler dying for the unjust rebel? This is no teaching of human mythology or dream of poetical imagination. This method of expiation is only known among men because it is a fact fiction could not have devised it. God Himself ordained it; it is not a matter which could have been imagined.
Excerpt taken from All of Grace by C.H. Spurgeon. This excerpt can be found in Chapter 5. Public domain.