In front of around 6,000 faithful, he spoke about hope as the overarching theme of the jubilee year.
John the Baptist, who baptised Jesus in the Jordan, had pointed the way to the kingdom of God, which had dawned with Jesus Christ.
According to the Pope, God's standards applied there, which differed significantly from those of the world and therefore gave hope.
At that time, many people had come to John at the Jordan and hoped for a new beginning in their lives.
Many of the faithful who come to Rome during the Holy Year and pass through the Holy Door in one of the great papal churches do the same.
Hope, said the Pope, "is not a character trait that one possesses or not, but a strength that one asks God for".
This is precisely the intention of the Holy Year.
The Holy Year is a major Catholic event that is usually celebrated every 25 years.
It began on Christmas Eve with the opening of the Holy Door of St Peter's Basilica.
Over the course of the year, there are numerous religious, cultural and social events and initiatives. So that as many pilgrims as possible can experience the Pope live, Francis not only holds his weekly general audience on Wednesdays, but also additional audiences on Saturdays.
More than 30 million additional visitors are expected in Rome for the "Giubileo 2025".