Luke 19:4

But he discovered a good device; running before he climbed up into a sycamore, and saw Him whom he had long wished for, i. e. Jesus, passing by.

He has well added, that our Lord was to pass that way, either where the sycamore-tree was, or where he was who was about to believe, that so He might preserve the mystery, and sow the seeds of grace. For He had so come as that through the Jews He came to the Gentiles. He sees then Zacchæus above, for already the excellence of his faith shone forth amidst the fruits of good works, and the loftiness of the fruitful tree; but Zacchæus stands out above the tree, as one who is above the law.

(Mor. 27. c. 46.) Or because the sycamore is from its name called the foolish fig, the little Zacchæus gets up into the sycamore and sees the Lord, for they who humbly choose the foolish things of this world are those who contemplate most closely the wisdom of God. For what is more foolish in this world than not to seek for what is lost, to give our possessions to robbers, to return not injury for injury? However, by this wise foolishness, the wisdom of God is seen, not yet really as it is, but by the light of contemplation.

But he climbs up to the top of a sycamore-tree, in that he rises above the sweetness of pleasure, which is signified by a fig, and subduing it, and so becoming more exalted, he sees and is seen by Christ.

Mystically, Zacchæus, which is by interpretation "justified," signifies the Gentile believers, who were depressed and brought very low by their worldly occupations, but sanctified by God. And he was desirous to see our Saviour entering Jericho, inasmuch as he sought to share in that faith which Christ brought into the world. Or the crowd, that is, the general habit of vice, which rebuked the blind man crying out, lest he should seek the light, also impedes Zacchæus looking up, that he might not see Jesus; that as by crying out the more the blind man overcame the crowd, so the man weak in the faith by forsaking earthly things, and climbing the tree of the Cross, surmounts the opposing multitude. The sycamore, which is a tree resembling the mulberry in foliage, but exceeding it in height, whence by the Latins it is called "lofty," is called the "foolish fig-tree;" and so the Cross of our Lord sustains believers, as the fig-tree figs, and is mocked by unbelievers as foolishness. This tree Zacchæus, who was little in stature, climbed up, that he might be raised together with Christ; for every one who is humble, and conscious of his own weakness, cries out, God forbid that I should glory, save in the cross of our Lord Jesus Christ. (Gal. 6:14.)