⁸ Zaccheus stopped and said to the Lord, “See, Lord, I am [now] giving half of my possessions to the poor, and if I have cheated anyone out of anything, I will give back four times as much.” ⁹ Jesus said to him, “Today salvation has come to this household, because he, too, is a [spiritual] son of Abraham; ¹⁰ for the Son of Man has come to seek and to save that which was lost.” (Luke 19:8-10, Amplified Bible - AMP)Zaccheus was already a Jew, an Israelite, therefore, by default, he should be a son of Abraham, so how come Jesus called him "a spiritual son of Abraham"? Because he was working for the Romans against the Israelites, he was considered dead to his own people. He was no longer considered a son of Abraham.When Zaccheus saw that his way was wrong, he rectified it. It is not that he never knew he was sinning or that he was "lost". In order for him to function, he probably deny whatever he was doing was wrong, just "doing his job". Reading the story, all Jesus did was telling him, "hey body, I'm going to go to your house and will be staying with you." Jesus didn't preach to him, or even had a "heart-to-heart" with him when Zaccheus made the promise. Zaccheus just volunteer the change.To the Jews, Zaccheus lost his salvation when he lived a life of a "notorious sinner" because he was "doing his job". A simple declaration by Jesus to stay at his house was enough for him to change his way. By doing so, Jesus declared Zaccheus "regained" his salvation because Jesus came for people just like him.The fact that we have and will sin is not the end of the world, because just because we have decided to follow Jesus does not make us any less of a sinner, just a saved lost soul. What matters is for us to be determined to change our ways. That is the way Jesus has provided for us.