Since the patristic period, the parable of the laborers in the vineyard (Matthew 20:1-16) has been detached from its context and understood as a parable about Jews and Gentiles (Irenaeus) or about early and late conversion (Origen). Those are, I think, valid uses or applications of the parable, but the parable itself is set in a discussion about wealth, sparked by the exchange with the rich young man (19:16-22).

The unity of the passage is evident in several ways.

First, the man, whom we later learn is young, comes to Jesus and asks him what he has to do to have eternal life. Jesus responds in a way that leaves him grieved, and he goes away. The exchange that Jesus has with His disciples afterward is still on the same theme – wealth and salvation and rewards. That is the theme to the end of chapter 19, where Jesus, abruptly, says that the “first will be last and the last first,” and this introduces, and concludes the parable (20:16). So there’s a seamless movement from the rich ruler to the parable.

In addition, the passage is put together in a way that unifies the whole passage. There’s a frame around the last half of chapter 19. The man asks about “eternal life” (v. 16), and Jesus says that the climactic inheritance of His disciples will be “eternal life” (v. 29). Plus, 19:30 and 20:16 match neatly, though they are themselves reversed. So, it seems that the passage divides into two sections, 19:16-29 and 19:30-20:16.

Those are two sections of the passage, but on the other hand the whole of the passage is also framed by some important themes. In particular, the young man asks what “good” he must do to enter life, and Jesus answers by talking about the good: “Why do you ask me concerning the good? There is One who is good,” implicitly God (19:16-17). The passage ends with the lord of the vineyard saying “Is it not lawful for me to do what I wish with what is my own? Or is your eye evil because I am good?” The owner of the vineyard, who clearly represents God, is the “One who is good,” and the parable displays His goodness.