In Romans 7, Paul says that freedom from law is actually the basis for our freedom from sin. He uses the example of a married woman who by Law is accountable to her husband. But when her husband dies, she is free from that responsibility.
Yet although the wife is the one who has been freed from the law, she didn’t die at all; her husband did! And so it is with us. By comparison, we’re like the living wife rather than the dead husband when talking about our own death to sin. In Christ, we are just as dead to law in regard to our sin as she is to the commandment which once governed her marriage.
God has acquitted His children of wrongdoing because the punishment for sin—that is, separation from Him—is no longer enforced. This is the key to understanding the true nature of our death to sin.