He was trying to see who Jesus was, but could not see over the crowd because he was small in stature.
Many, no doubt, were converted to the faith of Christ of whom no account is kept in the gospels; but the conversion of some, whose case had something in it extraordinary, is recorded, as this of Zaccheus. Christ passed through Jericho, Luk 19:1. This city was build under a curse, yet Christ honoured it with his presence, for the gospel takes away the curse.
Commenting on Luke 19:1-10
And he ran before,.... Jesus, and the company that was with him; so very desirous was he of seeing him: and climbed up into a sycamore tree to see him: which sort of trees were very common about Jericho: hence we read of, , "beams of sycamore" in Jericho, which those that were strong took up in their arms, and the owners stood and devoted...
Verse 3. Who he was. Rather what sort of person he was, or how he appeared. He had that curiosity which is natural to men to see one of whom they have heard much. It would seem, also, that in this case mere curiosity led to his conversion and that of his family. Comp. .