Zacchaeus the tax collector is a familiar story in Luke 19. This despised man within Jewish culture has an encounter with Jesus and extraordinary generosity is the outcome.
To understand how radicle Jesus was you have to understand how a tax collector was perceived in Israel in the Roman era. Jericho was one of the three regional tax centers in Israel. Here was the man who was the chief tax-gatherer. He was the administrator of taxation under the Roman occupying government and because of that, he was rich, very rich.
Some of his wealth was because he had a job and Rome compensated him for it, but he amassed extreme illegitimate wealth because he extorted and robbed in every way that he could. He was surrounded by criminals who took the money that he demanded one way or another.
He was despised at the highest level of anybody in the Jewish culture because he had purchased a Roman tax franchise and is essentially endorsing the occupying, idolatrous, and pagan enemy of Rome.
He can't go to the synagogue and he can't participate in regular Jewish life. His friends are prostitutes and other sinners considered the dregs of society.
Jesus spent a lot of time with these kinds of people, so much so, he was accused of being a drunkard and sinner. Jesus invites Himself to Zacchaeus's house which raised religious eyebrows and Zacchaeus is transformed by this visit. We don't know what was said but the outcome was salvation and outrageous generosity. He donates 50% of his wealth to the poor and promises to restore wealth gotten illegally to be repaid fourfold.
What's the point? When people have an encounter with Jesus, lots of different things happen, here it is spontaneous generosity. He didn't just repay those he extorted from, he gave 50% on top of that. If you struggle with the tithe (10%) be careful, you might end up giving 50%.
I happen to think 10% is a floor for New testament giving and generosity. I think we should be striving to give above and beyond 10%. As Jesus said, it's more blessed to give rather than receive.