Death is the punishment for sin (Gen. 2:15–17), so if someone dies, they have been reckoned a sinner. However, one can be reckoned a sinner without ever having committed an actual, personal sin, without ever having willfully broken a commandment. We noted yesterday that this is true of babies, for many die without ever having made the individual choice to break a specific law. But it is also true of Christ, who died though He never violated God's commandments. Jesus "committed no sin, neither was deceit found in his mouth" (1 Peter 2:22), yet on the cross "for our sake [God] made him to be sin who knew no sin" (2 Cor. 5:21). His people's sin was put on His account, and God regarded Him as guilty. This guilt was not His because He personally sinned but because God imputed sin to Him.
These facts help us to make sense of Romans 5:12–14. When Paul says all have sinned (v. 12), he is not speaking of the personal sins we have committed on our own. (Though all of us certainly have many personal and individual violations of God's law on our records.) Instead, He means that we bear the guilt of Adam by imputation. The "one trespass" of Adam "led to condemnation for all men" (v. 18). "In Adam all die" (1 Cor. 15:22).
People do die because they are guilty of personal disobedience in which no one else shares. When we hate a brother in our hearts, for example, we alone are guilty (Matt. 5:21– 26). But even before we sin in such an individualized way, we are guilty before God. The guilt unique to us is secondary—in a sense—to Adam's guilt that we possess by imputation, for we can and do die even before we commit sins that are exclusively our own. Paul focuses on the primacy of Adam's guilt imputed to us in Romans 5:12–14 when he says that people die even though sin is not counted where there is no law, that is, the Mosaic law. It is not that we are sinless if we do not know God's inscripturated law, for Paul has also said that those without access to the Mosaic law break the law of their consciences (Rom. 2:12–16; 3:23). The Apostle means that there is a difference between violating the law of our consciences, a law we often find difficult to discern, and violating something that we clearly know to be objectively wrong because the Spirit has given it to all people via Scripture. Violating unambiguous standards that God gives via objective, tangible, external revelation is worse then violating the conscience because the Lord has gone to greater lengths and shown Himself more kind to us by making His rules clear to us in His Word.
Imputation of sin reveals the principle of federalism, which we will discuss more over the next few days. Today we note that we do not come into the world in a state of moral neutrality. We are not born innocent, but we are already deserving of death. Since the fall, the naturally-conceived-and-born sons and daughters of Adam are legally guilty of sin and subject to its consequences. If this were not so—if we were legally neutral before God—we would not need a Savior.