Jesus is entering Jericho on his way to Jerusalem when he encounters Zacchaeus up a tree and out on a limb. He calls to him and tells the notorious tax collector (read: "loan shark.") that he's coming to dinner at his house. In this short sequence, we see the story of redemption. Christ is on his way to Jerusalem to climb out on his own limb for us, to free us from sin. Zacchaeus is the last person anyone would see as a disciple of Christ, but he goes out on the limb to contact Christ. In this story, we see how God and man interact. Christ has opened the way for us, and we travel to meet him. This is not a passive relationship at all. God came to meet us through the death and resurrection of Jesus Christ, and we come to God through acts of penance, which is transformation, not punishment. Together with God we become what God created us to be. (See the Wisdom reading for today.)
Obviously, "going out on a limb" means taking a risk. Zaccheaus, with his own terms of restitution, was taking a huge risk. The question we have to ask ourselves today is what risk do I need to take? What limb do I have to climb out upon to meet the Lord and become one with Him?