Luke 19:3 in the World English Bible
He was trying to see who Jesus was, and couldn’t because of the crowd, because he was short.
Context
2 And, behold, there was a man named Zacchæus, which was the chief among the publicans, and he was rich.
3 And he sought to see Jesus who he was; and could not for the press, because he was little of stature.
4 And he ran before, and climbed up into a sycomore tree to see him: for he was to pass that way.