There is no express marriage - Pope Francis

"There is no express marriage. The betrothal must be reassessed," the Pope said on Saturday evening.

In front of almost 90,000 people who attended the vigil in St. Peter's Square, the head of the Church called the Catholic faithful throughout the world to pray for the synod that opens on Sunday.

He asked them to pray especially for this synod that "recognizes, promotes and offers everything there is in the beautiful family, good and holy". The Synod will last three weeks and debates could be very contentious.

Several issues are on the agenda, including how the church should treat homosexuals faithful and couples who live together without being married. But also those who wish to take communion that are divorced and remarried after.

It is unlikely that the Church changes its doctrine, but some traditionalists fear that the Synod itself causes confusion on the ideals of the Catholic faith.

And those who want a significant change fear that this can occur in spite of the Pope’s calls that have often asked the priests to show mercy to the place of their misguided sheep.

Saturday night, the pontiff has not at all mentioned the coming out of gay priest, a Polish theologian of the Vatican who revealed his homosexuality. But then he spoke to some 90,000 faithful with lit candles on the St. Peter's Square, the Pope asked grimly. "What good light a small candle in the darkness around us?"

Pope Francis finally urged the Church to be an "open house" and a "family which corrects without humiliating, that educates by example and patience."