Rubén Díaz Sr., the Bronx state senator, Pentecostal minister and steadfast opponent of same-sex marriage, gathered his flock on Sunday for a rally on the steps of the monumental Art Deco courthouse in the Bronx, serenaded by church bands and an ear-piercing soundtrack of Latin song.

The slogan they shouted, aimed at the State Legislature, said it all: "One Man. One Woman. God's Will."

Across the street, on a more modest staircase, stood another Diaz, who had come out to the Grand Concourse on Sunday with a far different intent.

Erica Diaz, 22, a gay woman who is the senator's granddaughter, wanted her grandfather's supporters to know whom they were opposing.