The reason why an atonement was necessary, was the inflexible nature of divine justice. This attribute leads the Ruler of the universe to render to every one his due; to treat every one according to his character. The justice of God was manifested in giving to man a righteous law, and annexing a penalty exactly proportioned to the demerit of every transgression. Such a penalty being annexed to the law, it is evident that to execute it is a righteous thing; and when this penalty is incurred by transgression, the Judge of all the earth, acting justly, must inflict it. He cannot deny himself. “He is not a man that he should lie, or the son of man that he should repent.” If the penalty of the law might be set aside in one instance, it might in all, and then government would be at an end. Indeed, no reason can be assigned for a difference; if one sinner is exempted from punishment, the same treatment should be extended to all; for, in the administration of law and justice, there should be uniformity….

Archibald Alexander, A Brief Compend of Bible Truth, 109.