Spurgeon: Justification is forensic, an act of God's free grace alone

Now, what is the meaning of justification? Divines will puzzle you, if you ask them. I must try the best I can to make justification plain and simple, even to the comprehension of a child. There is not such a thing as justification to be had on earth for mortal men, except in one way. Justification, you know, is a forensic term; it is employed always in a legal sense. A prisoner is brought to the bar of justice to be tried. There is only one way whereby that prisoner can be justified; that is, he must be found not guilty; and if he is found not guilty, then he is justified—that is, he is proved to be a just man. If you find that man guilty, you cannot justify him. The Queen may pardon him, but she cannot justify him. The deed is not a justifiable one, if he were guilty concerning it; and he cannot be justified on account of it. He may be pardoned; but not royalty itself can ever wash that man's character. He is as much a real criminal when he is pardoned as before. There is no means among men of justifying a man of an accusation which is laid against him, except by his being proved not guilty. Now, the wonder of wonders is, that we are proved guilty, and yet we are justified: the verdict has been brought in against us, guilty; and yet, notwithstanding, we are justified. Can any earthly tribunal do that? No; it remained for the ransom of Christ to effect that which is an impossibility to any tribunal upon earth. We are all guilty. Read the 23rd verse, immediately preceding the text—"For all have sinned, and come short of the glory of God." There the verdict of guilty is brought in, and yet we are immediately afterwards said to be justified freely by his grace.

Now, allow me to explain the way whereby God justifies a sinner. I am about to suppose an impossible case. A prisoner has been tried, and condemned to death. He is a guilty man; he cannot be justified, because he is guilty. But now, suppose for a moment that such a thing as this could happen—that some second party could be introduced, who could take all that man's guilt upon himself, who could change places with that man, and by some mysterious process, which of course is impossible with men, become that man; or take that man's character upon himself; he, the righteous man, putting the rebel in his place, and making the rebel a righteous man. We cannot do that in our courts. If I were to go before a judge, and he should agree that I should be committed for a year's imprisonment, instead of some wretch who was condemned yesterday to a year's imprisonment, I could not take his guilt. I might take his punishment, but not his guilt. Now, what flesh and blood cannot do, that Jesus Christ by his redemption did. Here I stand, the sinner. I mention myself as the representative of you all. I am condemned to die. God says, "I will condemn that man; I must, I will—I will punish him." Christ comes in, puts me aside, and stands himself in my stead. When the plea is demanded, Christ says, "Guilty;" takes my guilt to be his own guilt. When the punishment is to be executed, forth comes Christ. "Punish me," he says; "I have put my righteousness on that man, and I have taken that man's sins on me. Father, punish me, and consider that man to have been me. Let him reign in heaven; let me suffer misery. Let me endure his curse, and let him receive my blessing." This marvellous doctrine of the changing of places of Christ with poor sinners, is a doctrine of revelation, for it never could have been conceived by nature. Let me, lest I should have made a mistake, explain myself again. The way whereby God saves a sinner is not, as some say, by passing over the penalty. No; the penalty has been all paid. It is the putting of another person in the rebel's place. The rebel must die; God says he must. Christ says, "I will be substitute for the rebel. The rebel shall take my place; I will take his." God consents to it. No earthly monarch could have power to consent to such a change. But the God of heaven had a right to do as he pleased. In his infinite mercy he consented to the arrangement. "Son of my love," said he, "you must stand in the sinner's place; you must suffer what he ought to have suffered; you must be accounted guilty, just as he was accounted guilty; and then I will look upon the sinner in another light. I will look at him as if he were Christ; I will accept him as if he were my only-begotten Son, full of grace and truth. I will give him a crown in heaven, and I will take him to my heart for ever and ever." This is the way we are saved, "Being justified freely by his grace, through the redemption which is in Christ Jesus." –C.H. Spurgon, Justification by Grace