It’s common to compare baptism to marriage. But it’s not often recognized that the image is a biblical one.
In expounding on the marriage analogy at the beginning of Romans 7, N.T. Wright (Paul and the Faithfulness of God, 892-3) notes the link back to the baptism exhortation in Romans 6.
In Romans 7, Paul envisions “a married couple, with the husband dying and the wife being free to marry again.” The image is complicated by the fact that “the death and the remarriage happen to the same person: ‘you died to the Law . . . so that you could belong to someone else.’”
Wright says that the image is explicable in terms of Romans 6, where the old man dies in baptism to Adamic life: “in 6.6, the ‘old human’ has died in baptism, ‘o that the bodily solidarity of sin might be abolished, and that we should no longer be enslaved to sin.’ That is the picture which Paul has in mind. The ‘marriage’ illustration develops the point of 6.3-14: the death that occurs (the Mesiah’s death, shared by the believer through baptism) sets a person free from the ‘old human,’ the ‘old Adam,’ to whom one was bound by the Law. Without that death, the Law still binds one to Adam, but with the death of the old Adam in baptism the Law no longer has a claim. The law is not the first husband, but the thing which binds ‘you’ to that first husband.”
In addition to making the connection between baptismal and marital “death and resurrection,” Paul’s argument indicates, surprisingly, that the Law bound Israel not to Yahweh but to Adam. The marital covenant of Sinai was a specification of an Adamic order, to which Israel had to die in order to enjoy the consummation of her marriage.