ROME — The coronavirus that is threatening the world and knows no religion has penetrated the high walls of the Vatican and come to the doorstep of Pope Francis and the elderly cardinals who live near him.

“For weeks now it has been evening. Thick darkness has gathered over our squares, our streets and our cities; it has taken over our lives,” Francis, who is 83 and had part of a lung removed during an illness in his youth, said in remarks hauntingly delivered on the steps of St. Peter’s Basilica Friday evening.

He spoke alone and before a vast and empty square, its cobblestones slicked with rain and reflecting the blue lights of the police locking down Rome to fight the virus. “We find ourselves afraid,” the pope added. “And lost.”

The remarks on such a dramatic and grand stage amounted to a change of course for the pontiff, who throughout the first weeks of the coronavirus crisis in Italy — now the world’s deadliest outbreak — tended to talk about other things, or addressed the issue via live stream. When he came down with a bad cold last month, he refused to address whether he had been tested for the virus; some employees have grumbled about offices having stayed open too long.