The Maryland legislature passed the Civil Marriage Protection Act. Voters will get the final say in a referendum. Some oppose same-sex marriage for religious reasons, which I believe are irrelevant.
The First Amendment guarantees freedom of religion and that the government cannot "establish" a religion. We are used to Judeo Christian laws but forget that our laws aren't based on the laws from the Bible. Crab-loving Marylanders wouldn't like Leviticus 11:10. Teenagers can be exasperating but we don't stone a "stubborn and rebellious son" (or daughter) to death, per Deuteronomy 21:18-21. I used not to cut the grass on Sunday, for fear of offending my neighbors, but they often cut theirs then. Exodus 35:2 prescribes the death penalty.
Religious opponents who testified at hearings quoted the Bible, making equally little sense. They may truly believe that their God established marriage in Genesis 1:28 and that homosexuality is an abomination based on Leviticus 20:13, but the Establishment Clause of the First Amendment guarantees that we don't have to agree.
In the 1960s, segregationists used the Bible to make dire predictions about society falling apart if desegregation was abandoned. But none of that actually happened. State Sen. Allan H. Kittleman remarked at a rally that his father didn't believe things that might happen ought to be a reason to oppose school desegregation. Neither does he believe gays and lesbians mustn't be allowed marriage equality.
In 1960s blacks refused to accept "separate but equal" from the Plessy v. Ferguson decision any longer. Gays and lesbians feel that way about civil unions. Blacks got the separate facilities, but they weren't equal until they demanded true equality. That's what gay and lesbian citizens are doing now.