‘The power of life and death is in the tongue,’ Senate chaplain says in a powerful prayer calling for unity.

“We deplore the desecration of the United States Capitol building, the shedding of innocent blood, the loss of life, and the quagmire of dysfunction that threaten our democracy.”

Those words, spoken by Barry C. Black, the Senate chaplain, resounded through the government chamber in the early hours of Thursday, as he declaratively closed a joint session of Congress marred by mob violence with a prayer.

Delivered moments after President-elect Joseph R. Biden’s victory was certified by lawmakers who had worked through the night, and hours after a violent crowd of rioters urged on by President Trump had threatened to derail the process, Mr. Black’s prayer cut through the chamber with force.

He condemned the violence of the day, acknowledged divisions in the nation and called for healing and unity.

A Seventh-day Adventist minister and former Navy rear admiral known for his penchant for brightly colored bow ties, Mr. Black has been the Senate’s official clergyman for nearly two decades. His prayers in the chambers have long been laced with rebukes for the infighting of the lawmakers surrounding him, and his words have often served as a conscience check for those on both sides of the aisle.

That was never more true than on Thursday morning, as he warned lawmakers that their words could have great consequences.

“These tragedies have reminded us that words matter, and that the power of life and death is in the tongue,” he said. “We have been warned that eternal vigilance continues to be freedom’s price.”

His prayer also urged new unity in the face of the deep divisions among lawmakers and within the country, driving home a need to “see in each other a common humanity.” He sought to move both the lawmakers and the nation forward, saying that God had “strengthened our resolve to protect and defend the Constitution of the United States against all enemies domestic as well as foreign.”

“Use us to bring healing and unity to our hurting and divided nation and world,” he said. “Thank you for what you have blessed our lawmakers to accomplish in spite of threats to liberty.”