Jesus is teaching a parable that is based off of Isaiah 5

The Song of the Vineyard

I will sing for the one I love a song about his vineyard:
My loved one had a vineyard on a fertile hillside.

He dug it up and cleared it of stones and planted it with the choicest vines.
He built a watchtower in it and cut out a winepress as well.
Then he looked for a crop of good grapes, but it yielded only bad fruit.