Tertullian, On Monogamy 13

When Paul writes to Timothy, he tells younger widows to marry, have children, and run a household (1 Tim 5:14). He addresses the very women he described earlier: widows who once committed to celibacy, stuck with it for a while, but then — after tasting Christ as their delight — decide they want to marry again. By doing so they pass sentence on themselves: they have broken their first pledge, the very faith that led them into widowhood and that they publicly professed, yet they do not persevere in it. That is precisely why Paul urges them to marry — not so they can rack up husbands every time widowhood tests them and they refuse to hold fast even in delight, but to keep them from later renouncing the original vow they took when they embraced widowhood.

We also find Paul writing to the Romans: "A married woman is bound by law to her husband while he lives; but if her husband dies, she is released from the law of marriage" (Rom 7:2–3). So if she joins another man while her husband is alive, she will be called an adulteress; but if her husband dies, she is free from that law, and marrying another man does not make her an adulteress (Rom 7:3). Now follow the next lines closely, so the interpretation that flatters you can be exposed. Paul says, "Therefore, my brothers, you also have died to the law through the body of Christ, so that you may belong to another, to him who was raised from the dead, in order that we may bear fruit for God" (Rom 7:4). He explains: "For while we were living in the flesh, our sinful passions, aroused by the law, were at work in our members to bear fruit for death. But now we are released from the law, having died to that which held us captive, so that we serve in the new way of the Spirit and not in the old way of the written code" (Rom 7:5–6).

If Paul commands us to die to the law through the body of Christ — and that body is the Church, which lives by the Spirit of newness, not by the letter of the old law — then he is pulling you out of the very law that releases a widow to remarry after her husband's death. He drives you into the opposite condition: having lost your husband, you must not marry. Under the old law you would not be counted an adulteress for marrying again after your husband's death; but precisely because you have now died to that law, the new condition brands you an adulteress if you remarry. You have departed from the law that once gave you permission, so that permission no longer applies.