St. Anthony began his Opus with Joel (2:22): "The tree that bears its fruit, the fig tree and the vine give their yield." This tree is further mentioned in the book of Wisdom:
"When because of him (the unjust man) the earth was flooded, it was Wisdom again who saved it, directing the course of the just by contemptible wood. This contemptible wood is the Cross of Christ; contemptible because 'accursed is anyone who is hanged on a tree,' where Christ, the Wisdom of God the Father, was scorned and derided: 'So you would destroy the temple and rebuild it in three days! Then save yourself! If you are God's Son, come down from the Cross !'" (Mt. 27:40)
On this contemptible tree, Christ saved the world.