Zacchaeus ran ahead and climbed a sycamore tree in order to see Jesus ( Luke 19:4).
The story is unique to this gospel. While a rich man, Zacchaeus provides a contrast to the rich man (in the previous cap. 18:18 of Luke) who cannot detach himself from his material possessions to become a follower of Jesus. Zacchaeus exemplifies the proper attitude toward wealth: he promises to give half of his possessions to the poor and subsequently he was the recipient of salvation.
His repentance is attested by his determination to amend his former ways and shows him as a true descendant of Abraham, the true heir to the promises of God in the Old Testament. Underlying Luke's depiction of Zaccheus as a descendent of Abraham, (the father of the Jews), is his recognition of the central place occupied by Israel in the plan of salvation.
"For the Son of man has come to seek and to save what was lost" - this verse sums up for Luke his depiction of the role of Jesus as savior in this gospel. (Stephen Hartdegen).