Sunday's Isaiah reading (Is 5:1-7) gives us the basis for the metaphor Jesus uses in the Gospel (Mt 21:33-43).
Following classic biblical imagery, Isaiah describes Israel as a non-producing vineyard planted by Yahweh. Though God has done everything necessary to harvest a terrific crop, the vineyard yields only "wild grapes."
"What more was there to do for my vineyard that I had not done?" Yahweh asks. "I will make it a ruin: It shall not be pruned or hoed but overgrown with thorns and briers; I will command the clouds not to send rain upon it. The vineyard of the Lord of hosts is the house of Israel."
This powerful prophetic allegory is so well-known that Jesus' audience immediately understands that He's talking about them when He begins His own allegory with the words: "There was a property owner who planted a vineyard, put a hedge around it, dug out a vat, and erected a tower."
But Jesus changes Isaiah's imagery. He both puts Himself into it as the property owner's son and adds the concept of "tenant farmers." The latter create the story's confrontation by refusing to turn over the owner's share of the grapes. Here, instead of destroying the vines, Jesus' owner brings "that wicked crowd to a bad end and leases the vineyard to others who see to it that he has grapes at vintage time."
Commentators and homilists often mention that the tenants are the Jewish leaders of Jesus' day and age; those who receive the new lease are the Gentile Christians, who now join the Jews as God's special people.
Yet few readers of this Christian allegory examine its Jewish counterpart carefully enough to notice Isaiah's definition of "wild grapes." "Yahweh looked for judgment, but see, bloodshed! For justice, but hark, the outcry!"
In the Hebrew Scriptures, "judgment" and "justice" always refer to relationships: ties with Yahweh and one another. Against this background, Isaiah reminds his people that, in place of relationships, Yahweh finds only bloodshed and outcries. Before anything else, our God checks on how well we're fulfilling our social responsibilities.
Because Jesus says nothing to contradict Isaiah's emphasis on relationships, we assume that relationships are the harvest He accuses the religious leaders of refusing to turn over. As a reformer, He knows how easily formal religion and "religious" people de-emphasize relationships and begin to stress ritual laws and regulations.
This change in emphasis not only avoids the "messiness" of relationships but also supplies religious folk with clear, unconfusing norms against which they can judge whether or not they're fulfilling God's will. It's far easier to determine if I've "attended Mass on Sunday" than to determine if I've "loved my neighbor."
This overriding desire to reform as Jesus reforms seems to be why Paul, coming from a background of obeying 613 detailed Torah laws, is so vague when he encourages the members of his Philippian community (Phil 4:6-9) to wholly direct their thoughts "to all that is true, all that deserves respect, all that is honest, pure, admirable, decent, virtuous, or worthy of praise."
He's talking about relationships, not laws. By definition, relationships are ethereal, fragile entities. Followers of Jesus must always live in that ambiguous realm of what they've learning and accepted, heard and seen about relationships.
From Sunday's readings, it's clear that we cease being either God's vineyard or the tenants of God's vineyard when we cease relating to others as God relates. When regulations replace a relating faith, reform is necessary.
As Jesus reminds us, if we don't reform, we could be replaced.