To answer that question, Moore said, the purpose of sexuality must be established.
"It's not just an individual matter. It's something that has to do with binding those two together in connection with future generations and with the generations that have come before," Moore, president of the Southern Baptist Ethics & Religious Liberty Commission, said in a video posted to The Gospel Coalition blog July 3.
Some gays and lesbians, Moore said, wrongly assume that Christians want to restrict marriage and not allow homosexuals to enjoy it.
"What we're saying is not, 'We don't want you to be able to get married.' We're saying that same-sex marriage is impossible based upon what sexuality and what marriage is," Moore said.
"So it's not that we're trying to disappoint our neighbors. We're saying this is for the good of human flourishing. And we love you -- that's the reason why not only do we say that we think there's some restrictions for you, there's some restrictions on us in terms of what this looks like," Moore said.
Baucham, pastor of preaching at Grace Family Baptist Church in Spring, Texas, took issue with homosexual activists who say, "It's not harming anybody. It's me in my bedroom."
"Well, the current debate about marriage explodes that myth. This is not private. This is pressing upon culture as a whole," Baucham said in the video.
Because activists have framed the debate in civil rights language, Baucham said, it's "the greatest farce ever" for them to say, "You can go ahead and practice your religion. This has nothing to do with you practicing your religion.
"If this is a civil rights issue, and if us not doing weddings for homosexuals or not hiring homosexuals becomes violating civil rights, then it is not conceivable that the church will be unharmed by this," Baucham, who is African American, said.
Baucham also made the point that legal decisions are based on principles and established precedent, and "right now the principle is sort of the Beatles' mentality: All you need is love."
"Well, if that's the case, if marriage is based on popular opinion and who loves each other, the 50-year-old man and the 12-year-old boy, the man and his daughter, so on and so forth," Baucham said.
Greear, pastor of The Summit Church in Durham, N.C., said Christians should challenge the principle that just because something doesn't harm it can be removed from the realm of morality.
"If you cheat on your wife and she never finds out about it and you lie about it, is it wrong? I think most people would say yes because lying is inherently wrong," Greear said.
Harm does not always reveal itself immediately, Greear said, urging people to consider the long-term effects of gay marriage.
"For as long as there has been human history, the sanctuary into which families have been brought forward has been a monogamous relationship between two opposite genders when they learn to love the other, and that is what the Creator called marriage," Greear said.
Moore said the language that is being used in the gay marriage debate is something to which Christians have already surrendered.
"One of the reasons why this is such a confusing thing for a lot of evangelical teenagers is because we have been talking as though marriage is an individual matter between two people," Moore said.
In wedding ceremonies, couples are writing their own vows, dictating the terms and focusing on their big day, Moore said. "That's not what marriage is in a Christian context."
For a long time in churches, people have advised newly married Christian couples to wait a while before having children so that they're able to enjoy one another "as though you can't enjoy one another raising up children together," Moore said.
"You're already surrendering to the terms and the rest of the culture says, 'Well, if that's what marriage is, is celebrating a relationship between two people, we have a relationship, why shouldn't we do this?' So I think we've got to back up and reclaim in our own churches a longer, bigger definition of what marriage is and start grounding that back in Ephesians 5 rather than the ways that we've accommodated," Moore said.
The church must be involved in the gay marriage debate, Baucham said, because "we don't take the truth and hide it under a bushel."
Moore mentioned critics who say the church should just let the world redefine marriage while the church maintains Christian marriage within its walls. That attempt was made with the divorce culture, he said, and it transformed the nature of the church.
Also, such a passive response is unloving toward neighbors, Moore said. "Divorce hurts kids, hurts families, hurts the entire social fabric. So does the expanding out of marriage to where marriage doesn't mean anything anymore," he said.
Regarding why the state even needs to be involved in marriage, Moore said the state "doesn't have anything to do with registering people as friends," but it does have an interest in male/female marriage "because male/female marriage can lead to something very dangerous for the state, and that is children." The state has a responsibility, Moore said, to determine who is accountable for an abandoned child.
Baucham said, and Moore agreed, that the state doesn't have the authority to define marriage but it does have to acknowledge the definition.
Greear referenced John the Baptist, who was beheaded for saying King Herod should not have been sleeping with his brother's wife.
"You can hear the critics today who say, 'Well, see, that's what you're going to get for messing around in politics. Of course Herod's going to sleep with his brother's wife 'cause they're the world and we've got to let the world be the world,'" Greear said.
The spirit of John the Baptist's enemies is at work in the world today, Greear said, but the successors of John the Baptist too often are silent.
Erin Roach is assistant editor of Baptist Press. Get Baptist Press headlines and breaking news on Twitter (@BaptistPress), Facebook (Facebook.com/BaptistPress ) and in your email ( baptistpress.com/SubscribeBP.asp).
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