When Jesus asks, “What do you think?” (21:28) one has to hear the question in the context of their previous refusal to answer a question about the person and ministry of John the Baptist. Jesus does not allow the Jerusalem leadership’s previous strategic silence to pass into obscurity. Since the new question is about characters in a story, it is indirect, and the leaders cannot avoid answering it. Their own answer will likely expose the weakness of their human authority.
Matthew, more than the other gospels, has an emphasis on deeds (or bearing fruit). Long (Matthew) points out this emphasis:
This parable is, in its own way, a narrative depiction of Jesus’ earlier statement in the Sermon on the Mount “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but only the one who does the will of my father in heaven” (Matt. 7:21). [p. 243]
The short parable of the Two Sons emphasizes that deeds are more important than words. On one level, this short parable addresses the church/synagogue tension present in Matthew’s community. The synagogue was the people who had said “Yes” to God, but who had failed to go and work. They were not doing God’s will. The church, especially with “sinful” Jesus and Gentile converts, were those who originally had said “No” to God, but who had changed their minds/hearst and did what God had asked.
However, related to this is the warning that even the church, who are now people who have said “Yes” to the Messiah, could become those who say the right words, but fail to act on them. It is a parable and warning for the people of faith then as well as today.
“Which of the two did his father’s will?” Depends on the text you read. There is considerable variation in the MSS and other older texts for the form of the parable and the subsequent answer to Jesus’ question. There are three main variants: (a) The first son refuses and then goes; the second promises and then fails; and the leaders approve the first. (b) The first promises and then fails; the second refuses and then goes; and the leaders approve the second. (c) The first refuses and then goes; the second promises and then fails; and the leaders approve the second. [There are cultures in which the very act of saying “no” to one’s father is a far greater offense than not doing what the father asks. But it is perhaps that both sons need to change.] Scott (Hear Then the Parable) suggests that both sons are wrong. Scott frames it in the sense of honor — a son who publicly says “no” to his father is shaming his father.
When the parable hearer is asked to choose between the two sons, a dilemma arises. Both sons have insulted the father, one by saying no, the other by saying yes but doing nothing. But one comes to the family’s aid by going into the vineyard and upholding family solidarity, while the other maintains the family’s good name by appearing on the surface to be a good son. Would the father choose to be publicly honored and privately shamed, or publicly shamed and privately honored? In the first century C.E. that is not much of a choice. The real question is with which one he would be more angry. But in being forced to choose, he must choose between the apparent and the real, between one who appears to be inside the family and one who appears to be outside. [p. 84]
That being said, the third variants [c] has the Jewish leaders approving words rather than deeds. This puts them in a bad light even before Jesus comments on their behavior, and it may have been for that reason that some scribes and translators preferred this reading that makes the Jewish leaders speak in the very way that Jesus will charge them with having acted. But this last option can hardly have been the original intention of the story, since Jesus’ response does not challenge their answer, but rather charges them with not having lived up to it. Their reading of the story, he implies, is right, but their correct thinking is belied by their actual behavior. The reading as translated in our text is agreed by most commentators to represent the original form of the story and response.
Changing. This parable is about doing the will of God (v. 31). The question, “What is God’s will for my life?” is one that Christians often ask. However, answering that question with an unreflective “obeying God and working in the fields” too easily leads to an idea that one is able to work/earn one’s salvation. But then again, relying on faith alone can reduce action to a meaningless afterthought to one’s words.
The key to this parable is the word metamelomai. Although the NAB (Catholic Bible) translates it with the sense of changing one’s mind,” (vv. 29, 32) that is not the most literal understanding of this word. Usually the idea of “changing one’s mind” or “repenting” is conveyed by the Greek word metanoeo. One wonders if Matthew’s use of the word metamelomai points to something more subtle.
The prefix meta = “change” begins both words. The verb noeo is related to activities of the mind (nous). The verb melo has the sense “to care for,” so we might translate metamelomai as “changing what one cares about” or “to change what one is most concerned about.” – or desires. It could be that v.29 might be translated as: “He answering said, “I am not willing,” but later having a change of heart, he went.”
We might say of the religious leaders of v. 32, “They would not change their hearts” – or to use an OT phrase: “Their hearts were hard.”