Very few conversions happen in an instant. Often conversion is a long process, with various little conversions, until there is a “tipping point,” an event that brings a person to a turning point, where a decision has to be made.
For St. Francis, I think this was his encounter with the leper. As he himself wrote in his Testament:
The Lord inspired me, Brother Francis, to begin a life of penance in this way: for when I was in sin, it seemed very bitter for me to see lepers. And the Lord Himself led me among them and I had mercy on them. And when I left them, what had seemed bitter to me was turned into sweetness of soul and body; and afterwards I lingered a little and left the world.
Francis began to see in the poor Christ. Nikos Kazantzakis, in his highly speculative novel Saint Francis, has Francis explain this to Brother Leo:
“This, Brother Leo, is what I understood: all lepers, cripples, sinners, if you kiss them on the mouth—”
He stopped, afraid to complete his thought.
“Enlighten me, Brother Francis, enlighten me, do not leave me in the dark.”
Finally, after a long silence, he murmured with a shudder:
“All these, if you kiss them on the mouth— O God, forgive me for saying this— they all. . . become Christ.”
This, though, is not far from the experience of Francis. Andre Vauchez refers to the Assisi Compilation which has Francis reflecting:
When you see a poor person, he said, you must consider that person in the name of the one who comes, that is, the Christ who took upon himself our poverty and our infirmity. Thus the poverty and infirmity of this person are the mirror in which we must contemplate in love the poverty and infirmity that Our Lord Jesus Christ suffered in his own body in order to save humankind.
To see Christ in the poor person in front of me, to respond in love – that is the beginning of conversion.