The Bible never says that Adam and Eve married. To consider they had children without the benefit of marriage is disconcerting to many; it assaults our traditional idea of matrimony and having kids.
The Bible, however, does refer to Eve as Adam’s wife and Adam as Eve’s husband. Well isn’t that marriage? Maybe it is, maybe it’s not. Consider Abraham and Sarah. Sarah gave her slave Hagar to Abraham to sleep with him and make a baby. The Bible then refers to Hagar as Abraham’s wife, even though no marriage took place.
Based on these two stories, it seems the biblical idea of becoming husband and wife is connected to sex, not marriage. After all, as soon as Eve is created the Bible says man will leave his parents, be united to his wife and they will become one. I think the idea of becoming one implies permanence, a lifelong sexual commitment. Getting married isn’t mentioned. After this, in the next verse, Eve is called Adam’s wife.
Marriage, by the way, isn’t cited in the biblical timeline for several centuries, some eight generations later (remember people lived for hundreds of years back then). The first occurrence of marriage is with Lamech, the father of Noah. Some Bible scholars place extra emphasis on the first mention of a word in the Bible, using it to frame our understanding of the word. This gives us another pause, for the first mention of marriage is in reference to polygamy, as in “Lamech married two women.” This is certainly a perversion of the idea of two people becoming one.
In all this, I’m not suggesting we disregard marriage, and I’m certainly not advocating polygamy. My suggestions are that our idea of traditional marriage may not be as biblical as we think, that we need to be careful before judging people with differing practices, and that sex does indeed make us one, as in husband and wife. May we view this oneness as sacred and lifelong.