The debate about marriage equality often centers, however discretely, on an appeal to the Bible. Unfortunately, such appeals often reflect a lack of biblical literacy on the part of those who use that complex collection of texts as an authority to enact modern social policy. As academic biblical scholars, we wish to clarify that the biblical texts do not support the frequent claim that marriage between one man and one woman is the only type of marriage deemed acceptable by the Bible’s authors....
In fact, there were a variety of unions and family configurations that were permissible in the cultures that produced the Bible, and these ranged from monogamy (Titus 1:6) to those where rape victims were forced to marry their rapist (Deuteronomy 22:28-29) and to those Levirate marriage commands obligating a man to marry his brother’s widow regardless of the living brother’s marital status (Deuteronomy 25:5-10; Genesis 38; Ruth 2-4). Others insisted that celibacy was the preferred option (1 Corinthians 7:8; 28).
Although some may view Jesus’ interpretation of Genesis 2:24 in Matthew 19:3-10 as an endorsement of monogamy, Jesus and other Jewish interpreters conceded that there were also non-monogamous understandings of this passage in ancient Judaism, including those allowing divorce and remarriage.
In fact, during a discussion of marriage in Matthew 19:12, Jesus even encourages those who can to castrate themselves “for the kingdom” and live a life of celibacy.
The authors of the piece—which appeared in today's Des Moines Register—go on to point out that the bible forbids interracial marriage (Ezra 10:2-11), that Jesus encouraged his followers to castrate themselves (!) and live a life of celibacy (Matthew 19:12), and that Martin Luther (heretic!) could find nothing about men being limited to "one woman" in the Bible (“I confess that I cannot forbid a person to marry several wives, for it does not oppose the Holy Scriptures”).