WATCH: Pope Francis Washes Feet of Elderly, Disabled And Muslim On Holy Thursday

Pope Francis washed the feet of 12 elderly and disabled people — women and non-Catholics among them — in a pre-Easter ritual designed to show his willingness to serve like a "slave."

Francis' decision in 2013 to perform the Holy Thursday ritual on women and Muslim inmates at a juvenile detention center just two weeks after his election helped define his rule-breaking papacy. It riled traditionalist Catholics, who pointed to the Vatican's own regulations that the ritual be performed only on men since Jesus' 12 apostles were men.

The 2014 edition brought Francis to a center for the elderly and disabled Thursday. Francis kneeled down, washed, dried and kissed the feet of a dozen people, some in wheelchairs. Of the 12 elderly and disabled people, nine were Italian, one was a Muslim from Libya, a young man from Cape Verde and an Ethiopian woman.   (WATCH YouTube video below from 38:00 to 45:00)

Francis told the faithful that he was performing the ritual to remind himself how to serve others, as Jesus did when he washed the feet of his apostles.

"Jesus made a gesture, a job, the service of a slave, a servant," he said. "And he leaves this inheritance to us: We need to be servants to one another."

Francis began Holy Thursday by presiding over Mass in St. Peter's Basilica celebrating the priesthood, the start of a busy four days of Holy Week commemorations and preparations for next week's canonization of Popes John Paul II and John XXIII.

During his morning homily Thursday, Francis urged his priests to exhibit joy, though he admitted that he too had suffered "moments of listlessness and boredom which at times overcome us in our priestly life."

All of those who had their feet washed receive help and support from the Don Gnocchi Foundatio,n which helps marginalized and isolated people through 30 healthcare and research centers specialized in rehabilitation throughout Italy, according to Vatican Radio.

Expert Physicist Dr. Furio Grammatica, Chair of the Centre for Innovation and Technology Transfer at the Foundation, said when they first received word that the pope wanted to visit on Holy Thursday they all thought it was "too fantastic to be true!"

Oh, but it was.

Based on reporting by the Associated Press.