Senator Marco Rubio of Florida, who has faced widespread condemnation for agreeing to speak at a conference alongside Christian conservatives who have denounced homosexuality and gay rights, used his speech to the group on Friday to warn of the costs of intolerance.

His remarks in Orlando, Fla., not far from the site of the massacre at a gay nightclub in June, were his most extensive yet in public on the subject of prejudice against gay, lesbian, bisexual and transgender people. And he struck a notably softer tone than during his campaign for the Republican presidential nomination, during which he repeatedly reaffirmed his opposition to same-sex marriage.

Using the shorthand “L.G.B.T.” several times, Mr. Rubio told the group that the perception that many Christians are anti-gay is harming their faith. He urged them to resist passing judgment on gays.

“Do not judge, or you will be judged,” he said, echoing a verse from the Bible.

“To love our neighbors we must recognize that many have experienced sometimes severe condemnation and judgment from some Christians,” he said. “They have heard some say that the reason God will bring condemnation on America is because of them — as if somehow God was willing to put up with adultery and gluttony and greed and pride, but now this is the last straw.”