In Our Mutual Joy, Newsweek's cover story for December 15, available today on magazine racks, Religion Editor Lisa Miller concludes there is nothing in the Bible prohibiting gay marriage and quite a bit for it.

Miller explains that the institution of marriage is continually evolving, and that “traditional marriage” as we think of it today did not exist during Biblical times.

Instead, Miller believes the Bible supports an argument for gay marriage.

Models of marriage in the Old Testament include polygamist and incestuous relationships, while in the New Testament Jesus remained single and “preached an indifference to earthly attachments – especially family.”

But, says Miller, most religious conservatives would point to Adam and Eve as evidence for their one man, one woman argument. “Therefore shall a man leave his mother and father, and shall cleave unto his wife, and they shall be one of flesh,” it says in Genesis.

Barnard University Bible scholar Alan Segal, however, says that that verse was most probably written by people who believed in polygamy.

Jesus himself remained unmarried and preached of a new family unit of believers, whose “bond in God superseded all blood ties.” He also said there will be no marriage in heaven and condemned those who divorce.

After fleshing out the Old and New Testaments, Miller finally comes out and states the obvious: The real problem with gay marriage for social conservatives is the gay, not the marriage.

And the Bible does say a few things about being gay, but she quickly dismisses Leviticus who says sex between men is “an abomination” by calling this a “throwaway line” – advice on how to live in an ancient Jewish world that is no longer relevant. Leviticus discusses how to bargain for a slave in greater detail, yet we give it no serious contemplation, Miller argues.

Which only leaves the notion that the tradition of marriage is somehow rooted in the Bible.

Here too Miller reasons otherwise: “The Bible was written for a world so unlike our own, it's impossible to apply its rules, at face value, to ours.” For instance, the Bible endorses slavery, provides conceptual shelter for anti-Semites, and recommends the death penalty for adulterers.

Today's marriage, in fact, bears little resemblance to Biblical marriage – monogamy has replaced an adulterous husband, whose title of master has evolved to equal partner in the 20th century.

And while the Bible offers little in the form of a marriage manual, it does endorse gay marriage, Miller insists.

“If we are all God's children, made in his likeness and image, then to deny access to any sacrament based on sexuality is exactly the same thing as denying it based on skin color,” she submits.

“Being with one another in community is how you love God. That's what marriage is about,” says the Rev. Chloe Breyer, executive director of the Interfaith Center in New York.

People get married “for their mutual joy,” she adds.

On the net: Miller's Our Mutual Joy