Jesus does not say anything about conversion, or giving up his day-job, or his fortune. Jesus says only that he desires to stay with this socially inert fellow. Zacchaeus is reduced, or re-sized to his dignity. He slides down the tree and welcomes Jesus joyfully. He also welcomes himself by reducing the size of his possessions. He fulfills the Jewish law of repayment and Luke has Zacchaeus do what the Rich Man in the previous chapter could not do, he gave half his riches to the “poor”. Conversion follows encounter; Jesus meets us and the relationship makes the difference in our actions. What is his motivation? My guess is that it comes from that we he himself inspired in the first reading.
But you have mercy on all, because you can do all things;
and you overlook people’s sins that they may repent.
For you love all things that are
and loathe nothing that you have made;
(Adapted from Larry Gillick, S.J.)