Jericho in the first century was a wealthy customs city. It sat at the crossroads of major trade routes coming out of Transjordan, and whoever controlled the tax franchise there controlled significant revenue. Zacchaeus was not a low-level tax collector — Luke specifies that he was archirelōnēs, the chief tax collector, the man at the top of the collection hierarchy. He would have supervised other collectors, taken a cut from their work as well as his own, and almost certainly enriched himself through overcharging, the universal practice of the system. The crowd's description of him as "a sinner" was not vague social disapproval — it was a specific category. Tax collectors worked for Rome, they collaborated with the occupying power, and they were excluded from synagogue life. They were considered ceremonially unclean.
Zacchaeus heard Jesus was passing through Jericho. He wanted to see him — Luke uses the verb zēteō, to seek, to look for purposefully. He couldn't see over the crowd because of his height. So he ran ahead and climbed a sycamore tree to watch Jesus pass underneath. The sycamore tree, Ficus sycomorus, is a broad, low-branching fig tree with hand-holds a child could manage. The image of a wealthy, powerful official in his official robes climbing a tree in public to see a rabbi is already remarkable. He wasn't asking for anything. He just wanted to see.
Jesus stopped under the tree and looked up. "Zacchaeus, make haste, and come down; for to day I must abide at thy house." He knew his name. He was already inviting himself — not waiting to be invited. The crowd murmured immediately: "he was gone to be guest with a man that is a sinner."
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.