Matthew 21:36-40

Mat 21:36 (KJB)
Again, he sent other servants more than the first: and they did unto them likewise.

God continued to send prophets to Israel and Judah but their stiffnecked rebellion cause them to reject every one. This shows the longsuffering of God but eventually the patience of God expires as His kindness is continually rebuffed. Eventually the northern kingdom went into Assyria and was never heard from again as they assimilated into their kingdom and Judah did not listen to the prophets which were sent to her either. (Jer 3:8-10 KJV) And I saw, when for all the causes whereby backsliding Israel committed adultery I had put her away, and given her a bill of divorce; yet her treacherous sister Judah feared not, but went and played the harlot also. {9} And it came to pass through the lightness of her whoredom, that she defiled the land, and committed adultery with stones and with stocks. {10} And yet for all this her treacherous sister Judah hath not turned unto me with her whole heart, but feignedly, saith the LORD.

Mat 21:37 (KJB)
But last of all he sent unto them his son, saying, They will reverence my son.

The parable continues to describe the long term relationship between Israel and God the Father. If the husbandmen had treated the servants so bad, normally there would not have been a son sent to them but the owner would have all the husbandmen arrested and brought up on charges. However, we are looking at the patience that God had with Israel and instead of destroying them, in the fullness of time He sent forth His Son to that vineyard. God the Father knew what was in store for His Son when He sent Him but for continuity, Jesus is telling the parable as a father who sends his son to see what is going on at the vineyard. He was counting on the husbandmen to at least reverence or respect his son.

Mat 21:38 (KJB)
But when the husbandmen saw the son, they said among themselves, This is the heir; come, let us kill him, and let us seize on his inheritance.

The husbandmen probably thought their little scheme was working and that the owner of the vineyard had died and maybe that is why there was no retribution for their actions. Then they see the son approaching and figuring that the owner had died, they thought that the son was coming to claim the vineyard as his inheritance. If they could kill him, then there would be no one to claim the vineyard and then they could do it through schemes and manipulation. They thought if they could kill him, then the vineyard was theirs. Here in this parable Jesus is foretelling His own death at the hands of the false religious leaders in league with the Romans. (John 11:50 KJV) Nor consider that it is expedient for us, that one man should die for the people, and that the whole nation perish not. Once they got rid of Jesus, they thought that their problems were over and they could once again run the country through their evil manipulations.

Mat 21:39 (KJB)
And they caught him, and cast him out of the vineyard, and slew him.

It seemed that the husbandmen had finally gotten their way because when the son came into the vineyard, they seized him and slew him outside of the vineyard. If they had slain him inside the vineyard, then the soil would be defiled and nothing would be allowed to be grown there. This is the perfect parable as it describes perfectly the attitude that Jesus faced. The religious leaders wanted to hold on to their lucrative positions and wanted nothing to interfere with that and did not care if that included murder in their plans. They hated Jesus because He exposed their hearts as well as their actions and if they could kill Him, then their problems would be solved, so they thought.

Mat 21:40 (KJB)
When the lord therefore of the vineyard cometh, what will he do unto those husbandmen?

Then Jesus finishes the parable by asking a very rhetorical question. Since the owner of the vineyard was not dead, when he finally shows up at his vineyard, what do you think that he will do to those who tried to steal his vineyard and those who killed his son? This parable is definitely related to Isaiah 5 where God speaks about Israel being that rebellious vineyard.