Here we read another passage foretelling and threatening judgment against faithless and unrighteous Israel. But we must not read it as only a warning against sin--it is also a promise of forgiveness and restoration for the penitent and humble sinner. Buried in the middle of the passage is the Lord's purpose, in it he tells Israel that the reason behind this judgment is not to punish his people but to "burn away your dross completely [and to] remove all your impurities" (Isaiah 1.25 CSB). No one likes discipline, yet again we must remember the purpose. "Do not despise the Lord's instruction, my son, and do not loathe his discipline; for the LORD disciplines the one he loves; just as a father disciplines the son in whom he delights" (Proverbs 3.11-12 CSB). The author of Hebrews quotes this very passage and adds, "No discipline seems enjoyable at the time, but painful. Later on, however, it yields the peaceful fruit of righteousness to those who have been trained by it" (Hebrews 12.11 CSB). If God disciplined us simply to punish from a ruthless and twisted desire, we could by no means consider him good. But over and over, the purposes of his discipline are expressly pointed out as for our good--as any good father or parent does.
The parable of the vineyard is an allegory, yet it presents a very clear teaching about the church, not national Israel, as the heirs to God's inheritance (i.e. the kingdom of God). The scribes and chief priest clearly understood Jesus' teaching in this way, hence their anger and ire against him (cf. v. 19). The early church consistently understood Jesus in this way also, as exemplified by St. Cyril of Alexandria, who wrote, "The farm was given to other farmers. Who are they? I answer the company of the holy apostles, the preachers of the evangelical commandments, the ministers of the new covenant. They were the teachers of a spiritual service, and knew how to instruct people correctly and blamelessly and to lead them most excellently to everything that is pleasing to God.… The God of all plainly reveals that the farm was given to other farmers and not only to the holy apostles but also to those who come after them, although they are not from Jewish blood" (Cyril of Alexandria, Commentary on Luke). The introduction in the 18th and 19th centuries of bicovenantalism and dispensationalism, respectively, and their notions that national Israel still somehow has a special place in the plan of God is novel in the overarching understanding of the church and simply not held or supported by the theological tradition of the universal church.