On the Feast of the Baptism of the Lord on Jan. 8, the pope baptized 13 babies and presided over Mass beneath Michelangelo’s frescoes.

In a brief off-the-cuff homily, the pope said that baptism is like a rebirth in Christ and therefore should be celebrated “like a birthday.”

“Dear parents, thank you for bringing your children here to have them enter the Church. This is a good day,” Pope Francis said.

"It is like a birthday because baptism makes us reborn in Christian life.

That is why I advise you to teach your children the date of their baptism as a new birthday: that every year they will remember and thank God for this grace of becoming a Christian.“

Following the homily, the Sistine Chapel choir sang the Litany of the Saints in preparation for the baptisms.

As in previous years, the pope told parents not to worry if their babies made loud noises during the ceremony.

He said: “The children are symphonic. ... Let them cry ... and breastfeed them freely. What is important is that today is a celebration."

The pope concelebrated the Mass with the papal almoner Cardinal Konrad Krajewski and Archbishop Fernando Vérgez Alzaga, president of the Governorate of Vatican City State.

The Feast of the Baptism of the Lord commemorates Jesus’ baptism in the Jordan River by St. John the Baptist.

The Catechism of the Catholic Church describes baptism as the “basis of the whole Christian life, the gateway to life in the Spirit ... and the door which gives access to the other sacraments.”

St. John Paul II began the papal tradition of baptizing children in the Sistine Chapel on the Feast of the Baptism of the Lord on Jan. 11, 1981.

The ceremony initially took place in the Pauline Chapel of the Apostolic Palace but was moved to the Sistine Chapel in 1983.

The event was reserved at first to babies of Swiss Guards but later expanded to include the children of Vatican employees.

To qualify, children have to be under one year of age and their parents must be married in the Church. Each child is accompanied in the Sistine Chapel by its parents, siblings, godfather, and godmother.

The family groups attend a rehearsal before the ceremony. During the event, the Vatican provides baby-changing tables in a nearby room in the Apostolic Palace.

“Today is a day to celebrate,” the pope said. “It is the celebration of the beginning of a beautiful Christian journey in which you will help your children to move forward. Thank you for your decision to bring them to be baptized.”