YUMA, Ariz. — The Rev. Victor Venalonzo opened his New Testament to the Book of Revelation on a recent Sunday and offered the men and women assembled at Iglesia Betania for a weekly Bible study a fresh look at its apocalyptic message.

“We’re failing as stewards of God’s creation, but these changes we’re seeing, that’s not God punishing us — we’re destroying ourselves,” Mr. Venalonzo told them. He alternated between English and Spanish, as he does all day in his Pentecostal church, which sits across from a trailer park and a half-mile from the Mexican border, serving Latinos who have recently arrived in the country and those born in the United States.

Until recently, the environment was never a topic that Mr. Venalonzo included in sermons to his congregants, who are mostly concerned about how they will pay their bills, find work, and keep their children on course in school and away from drugs.

But that has changed as development, drought, overuse and a drier, warming climate threaten the Colorado River, the source of the water they drink and use to irrigate the fields where they work. “Our lifeblood,” Mr. Venalonzo calls it.