Then he began to speak to them in parables. ‘A man planted a vineyard, put a fence around it, dug a pit for the wine press, and built a watch-tower; then he leased it to tenants and went to another country. (Mark 12:1)

A devout listener would hear in this preface the Song of the Vineyard from the prophecy of Isaiah

Let me sing for my beloved my love-song concerning his vineyard: My beloved had a vineyard on a very fertile hill. He dug it and cleared it of stones, and planted it with choice vines; he built a watch-tower in the midst of it, and hewed out a wine vat in it; he expected it to yield grapes, but it yielded wild grapes. (Isaiah 5: 1-2)

Jesus will take the allegory in a new direction, but the reference to Isaiah is purposeful. Isaiah makes explicit the allegorical roles and the moral nature of "wild grapes."

For the vineyard of the Lord of hosts is the house of Israel, and the people of Judah are his pleasant planting; he expected justice, but saw bloodshed; righteousness, but heard a cry! (Isaiah 5:7)

The gospel writers place this parable as being told inside the Temple, after the cleansing of the temple. This context - high on Mt. Zion, within the walls, beneath the great towers - would have sharpened the allegorical connections.