NOTES for Mat 21:33-46
Jesus gives old words new meanings. He tells His opponents the ancient parable from the prophet Isaiah (ch. 5) about how his (Isaiah's) friend planted a good vineyard, but thorns and wild grapes grew in it - yet the main meaning of this parable is radically changed by Him.
There the Lord did not receive fruit from His vineyard because His people did not fulfill the elementary moral demands of the law: they oppressed, killed, and deceived one another; this is precisely how their unbelief and "not knowing God" were revealed. Jesus' parable, on the contrary, is addressed to righteous, devout people who are certain that they are the very ones who know God and bring Him the best fruits. Here the "fruitlessness" of the vineyard is caused by the fact that its "vinedressers" do not know how to believe: they reject the prophets and Christ Himself. It is Jesus Himself who here takes the place of Isaiah's moral demands: He is the One in whom the people of God's Kingdom must bear fruit, and the One for whom all the vineyards of the earth were planted.