WATCH: Alabama's Roy Moore Takes a Stand Against Equality — in Texas

As both opponents and supporters of marriage equality rallied at the Texas state capitol in Austin Monday, the opponents had a special guest from another Southern state -- Alabama Supreme Court Chief Justice Roy Moore, who said he'd be guilty of treason if he didn't stand up against marriage rights for same-sex couples.

In speaking to the crowd, Moore invoked a Texas hero, Col. William Barret Travis, who in 1836 led forces battling the Mexican army at the Alamo in San Antonio, during Texas's fight for independence from Mexico. Travis died in the battle, along with all the men under his command.

"He took a stand in the face of an enemy that was far more numerous," Moore told attendees, who included dozens of Republican state legislators, according to The Texas Observer. "But he knew that he had to make a statement for the people of Texas, and that he would give his life. I hope I don't give my life, but I'm going to tell you this is a very serious matter. ... If we fail to stand up today, we will dishonor the memory, not only of Col. Travis, but all those who've died in the history of this great state."

Moore also made his oft-repeated statement that federal courts have no authority over state marriage laws, an argument he has made frequently in Alabama, where the state Supreme Court has blocked marriage equality, at least temporarily. Actually, he said, the authority to define marriage comes only from God.

"No court has any authority to redefine what God proposed in Genesis," Moore said. "The definition of marriage, you want it by man, it doesn't come by man, it comes from God." Watch his full speech below.

That view was shared by another speaker, Rev. David Wilson of Southcrest Baptist Church in Lubbock, pastor to state Sen. Charles Perry. Perry has introduced legislation that would prevent public officials in Texas from issuing marriage licenses to same-sex couples.

"If humans invented marriage, then polygamy, the taking of several wives, polyandry, the sharing of a wife by several husbands, same-sex marriage, marriage between an adult and a child, marriage between relatives, might seem normal and acceptable," Wilson said, according to the Observer. "But if man created marriage, then monogamy, the lifelong union of one man to one woman, would have no more intrinsic value than any other type of marriage. But marriage is not human invention, it is God's design."

Several state officials spoke as well. Lt. Gov. Dan Patrick said his opposition to equal marriage rights is "not about being anti-anyone. It's about being for marriage between a man and a woman" and that "it's not the federal government's business to tell Texans what to do in Texas on any issue," the Observer reports.

Attorney General Ken Paxton touted the lawsuit he filed last week against the Obama administration's effort to extend benefits to married same-sex couples under the federal Family and Medical Leave Act, even if they live in a state that does not recognize their marriage, such as Texas. "We're challenging the Obama administration once again, and we're going to win this case for Texas," he said, according to the Observer. "So please continue to pray for us, and I will pray that God blesses this great state of Texas." Paxton is also seeking to invalidate the marriage of two women, one of whom has ovarian cancer, who received a state-level judge's permission to marry in Texas, becoming the first same-sex couple married there.

Texas's ban on same-sex marriage was struck down by a federal court over a year ago, a ruling that is on hold while the state appeals. The U.S. Court of Appeals for the Fifth Circuit heard arguments in the case in January and has yet to issue a ruling. A state-level court has also struck down the ban, but its decision has not gone into effect either.

The marriage equality supporters' rally was low-key by comparison, with organizers trying to keep the pro-equality event physically separated from the other by using a different entrance at the capitol, The Dallas Morning News reports. "There is a very clear juxtaposition happening today," Equality Texas executive director Chuck Smith told the paper.

Andy Miller of Austin attended with his partner, Brian Stephens, and their 7-year-old son, Clark. He called the opponents' rally the "last gasp of prejudice" and said he was interested primarily in letting legislators know "what our lives are like." Of marriage equality, he told the Morning News, "We believe that it's something that fair-minded people will see as a civil rights issue."

A few counterprotesters had a presence at the opponents' event, with one carrying a sign noting that Rep. Tony Tinderholt, a marriage equality opponent, has been married five times. "I'm just wondering what gay marriage destroyed his previous four marriages," Gary Campbell of Austin told the Observer.

Earlier in the day, a group called the Coalition of African-American Pastors held a press conference at the capitol calling on U.S. Supreme Court Justices Elena Kagan and Ruth Bader Ginsburg to recuse themselves from the upcoming marriage equality case. Speakers also defended Texas's marriage ban and accused the LGBT rights movement of hijacking the African-American civil rights movement, the Observer reports.

LGBT people "were never beaten," said Rev. Bill Owens, coalition founder and president, in response to a reporter's query, according to the Observer. "They were never hung from trees. They were never fired for nothing. They were never treated like we were treated. You don't have a clue how we were treated in the South. You don't have a clue. ... This is not a civil rights movement. It's a civil wrong movement."

It's worth noting that a diverse group of other faith leaders spoke out in favor of marriage equality at a Texas rally in February.