Expositor's Bible Commentary Commentary Romans 7:3

"So then if, while the husband liveth, she be joined to another man, she shall be called an adulteress: but if the husband die, she is free from the law, so that she is no adulteress, though she be joined to another man." — Romans 7:3 (ASV)

To illustrate the binding character of the law, Paul uses the case of a woman who is married to a husband and remains bound by law in that relationship as long as her husband is living. During this time she is not free to seek another attachment; that may be done only in the event that the husband dies. Particularly in Jewish life this was the actual legal status of the wife, for she could not divorce her husband; divorce was a privilege granted only to the man. If the husband died, she was then released from “the law of marriage.”