VATICAN CITY — Looking tired but serene, Pope Benedict XVI told the thousands who gathered for his weekly audience that he was resigning for “the good of the church” — an extraordinary scene that unfolded in his first appearance since dropping the bombshell announcement.

The 85-year-old Benedict basked in more than a minute-long standing ovation when he entered the packed hall for his traditional Wednesday catechism lesson. He was interrupted repeatedly by applause, and many in the audience of thousands had tears in their eyes.

Benedict appeared wan and spoke softly, but his eyes twinkled with joy at the flock’s warm and heartfelt welcome. He repeated in Italian what he had told his cardinals Monday in Latin: that he simply didn’t have the strength to continue.

“As you know, I have decided to renounce the ministry that the Lord gave to me on April 19, 2005,” he said, to applause. “I did this in full liberty for the good of the church.”

He thanked the faithful for their prayers and love, which he said he had “physically felt in these days that haven’t been easy for me.” And he asked them to “to continue to pray for me, the church, and the future pope.”

A chorus of Italian schoolchildren serenaded him with one of his favorite hymns in German — a gesture that won over the pope, who thanked them for singing a piece “particularly dear to me.”