“The time has come” says Jesus.
He had already begun the groundwork – baptised by John and enabling him to recognise the arrival of the Lamb of God and also getting to know the core group of his disciples including Andrew and Simon Peter.
The arrest of John the Baptist marks a new phase.
The time has come to make know the coming of God’s Kingdom and our need to prepare for this by a change of heart and of our way of life.
We will only be motivated to change if we really believe that God is near and once we have begun to make that change our openness will make us more ready to recognise the Son of God for who he is.
The Church links this to the story of Jonah because Nineveh was the ancient foe of Israel and a symbol of evil.
If Nineveh could repent then no one is beyond God’s mercy or the touch of his grace.