They come together to protect the concept of traditional marriage.
Thousands marched from the National Mall to the U.S. Supreme Court to say that marriage should be between a man and a woman.
"What God has instituted man does not have the power, right or authority to alter," says Lalita Smith of Nashville. "We need to not play with the thing God has instituted."
The marchers came from all over the country, from pro-family and church organizations.
In front of the supreme court they prayed and exchanged heated words with gay marriage proponents.
Sarah Matas and her partner of seven years watched as the march for marriage demonstrated outside the nation's high court.
"All I'm asking for is a right to be married, to be married to someone I love," Matas says.
At a late morning rally on the mall speakers said marriage should not be redefined.
The Cox family came here from Carroll County, Md., to send a message to the nine justices.
"I definitely hope that they rule that marriage between a man and a woman if what is most important for the future of this country," says Abby Cox.