Mat 21:33 "Hear another parable. There was a master of a house who planted a vineyard and put a fence around it and dug a winepress in it and built a tower and leased it to tenants, and went into another country. Mat 21:34 When the season for fruit drew near, he sent his servants to the tenants to get his fruit. Mat 21:35 And the tenants took his servants and beat one, killed another, and stoned anot7her. Mat 21:36 Again he sent other servants, more than the first. And they did the same to them. Mat 21:37 Finally he sent his son to them, saying, 'They will respect my son.'
Mat 21:38 But when the tenants saw the son, they said to themselves, 'This is the heir. Come, let us kill him and have his inheritance.' Mat 21:39 And they took him and threw him out of the vineyard and killed him. Mat 21:40 When therefore the owner of the vineyard comes, what will he do to those tenants?" Mat 21:41 They said to him, "He will put those wretches to a miserable death and let out the vineyard to other tenants who will give him the fruits in their seasons."
As Jesus condemns the Jewish nation for their failure to keep the covenant God made with them he relates this parable that gives us a synopsis of their history of failure but also explains one reason why there was a Jewish nation to begin with. It turns out that the Jews were kind of a test case of humanity much like taking a water sample out of a well to see if the whole well is polluted or not. What we find is that they prove that sin has ruined the entirety of humanity and they also prove that the only way to be saved from sin is not by human effort but by a substitute.
What the parable teaches is that God separated the Jews from the rest of humanity and gave them every possible blessing if they would honor him as all men should. The OT constantly refers to this as Israel being a vineyard that is given good ground and water and hedged in from being trampled but this vineyard never produces any fruit; fruit being seen as taking these privileges and glorifying the Lord with them. What we find them doing for 1500 years is dishonoring the Lord in every possible way.
There are a couple of important lessons for us here. First of all we see the need for a better covenant that empowers us to live for the Lord. The main thing Israel does is prove that even if God promises them every physical blessing and even gives them a detailed set of rules so they know exactly what he wants, the natural man cannot love and obey what he by nature hates. It is only through a new heart or nature that we can love and serve God as we should.
Secondly this gives us a clear concept of what the Christian life is all about. In Christ we have been given every imaginable blessing of any value. Not necessarily physical blessings but meaning and fulfillment in this life and perfect bliss for eternity enjoying all the fullness of God forever. And all God asks is that we take these blessings and prove our love for him during this life even amid its difficulties. In this sense we are to do what Israel never could because the new covenant gives us the power to do what the old could not.
This means that as fallen creatures we can do what even our first parents could not. Although placed in a perfect environment they failed to serve the Lord above themselves. The power of the new covenant enables us to serve the Lord in the worst of circumstances.