VATICAN CITY (AP) — Pope Francis made a surprise entrance to St. Peter’s Square during a special Jubilee Mass for the sick and health workers on Sunday, marking his first public appearance at the Vatican since leaving t he hospital two weeks ago after a life-threatening bout with pneumonia.

The pontiff waved at the crowd of faithful that stood and applauded as he was pushed in a wheelchair unannounced to the front of the altar in the square. Some exclaimed, “I see the pope!” as his image first emerged on a big screen showing him passing through the Holy Door before being brought down a ramp to the altar.

“Good Sunday to everyone,’’ Francis said, speaking into a microphone, which he tapped to make sure it was working on a second attempt. “Thank you very much.”

The pontiff’s voice sounded stronger than when he addressed well-wishers outside of Gemelli hospital on the day of his release March 23, after a five-week hospital stay.

He wore nasal tubes to receive supplemental oxygen, which the Vatican says is being gradually reduced. As he waved and blessed the crowd, his arm movements remained limited — which his doctor said was not related to his illness but to an unspecified trauma suffered before his Feb. 14 hospitalization.

After the Mass, the pontiff greeted some of those who assisted in the service, many who bowed to kiss his hands. He exited the square through the Holy Door.

Pope shares his experience of being sick

Francis has just completed two weeks of at least two months of doctor-ordered rest as he continues physical, respiratory and speech therapy, as well as treatment for a lingering lung infection.

The pope referred to his experience with illness in both the traditional Sunday blessing and the homily read by Archbishop Rino Fisichella, organizer of the Holy Year that is expected to bring some 30 million pilgrims to Rome.

Addressing the sick among the crowd, the pope said in the homily read by Fisichella that “In this moment of my life I share a lot: the experience of infirmity, feeling weak, depending on the others for many things, needing support.

“It is not easy, but it is a school in which we learn every day to love and to let ourselves be loved, without demanding and without rejecting, without regretting, without despairing, grateful to God and to our brothers for the good that we receieve, trusting for what is still to come.”

He also urged the faithful not to push the fragile from their lives “as unfortunately a certain mentality does today. Let’s not ostracize pain from our surroundings. Let’s instead make it an opportunity to grow together, to cultivate hope.”

In the traditional Sunday blessing, he offered prayers for doctors, nurses and health care workers “who are not always helped to work in inadequate conditions, at times the victims of aggression. Their mission is not easy and must be supported and respected.”

The faithful were moved by the pope’s unexpected appearance.

‘’It was beautiful, something completely unexpected because I didn’t think I would see the pope,” said Pasquale Citrolo from Trapani, Sicily. “Instead he gave us this gift.”

Linda Elezi, from the Adriatic coastal province of Ancona, said she was touched by the pope’s “surprise.”

“We pray for him every day, and he prays for us, and for peace and for all the wold, because that is the message of our pilgrimage today: Bring peace to all the world,” she said.