The verb metamelomai is used twice in Jesus’ parable of the two sons, first in verse 29, and then in verse 32. As noted in a previous posting, this verb is weaker than the verb (metanoiō) used by John the Baptist in Matthew 3 and Luke 3, and by Jesus in preaching to the crowds. The KJV and ASV render metamelomai in both of these verses as “repented” or “repented himself,” but most modern translations render the two instances as different words, in much the same way as does the WEB:
28 But what do you think? A man had two sons, and he came to the first, and said, ‘Son, go work today in my vineyard.’ 29 He answered, ‘I will not,’ but afterward he changed his mind [metamelētheis], and went. 30 He came to the second, and said the same thing. He answered, ‘I go, sir,’ but he didn’t go. 31 Which of the two did the will of his father?” They said to him, “The first.” Jesus said to them, “Most certainly I tell you that the tax collectors and the prostitutes are entering into the Kingdom of God before you. 32 For John came to you in the way of righteousness, and you didn’t believe him, but the tax collectors and the prostitutes believed him. When you saw it, you didn’t even repent [metamelēthēte] afterward, that you might believe him.
However, it is noteworthy that, even though Jesus used this weaker verb in this parable, the result of the first son changing his mind in verse 29 was that he actually went into the vineyard and did as his father had asked. His change of heart was accompanied by action. This observation is particularly relevant given the context of the parable—Jesus’ answer to a challenge to his own authority.
Earlier in Matthew 21, Jesus had cast the money changers out of the Temple, and had in the process very provocatively quoted Jeremiah 7:11, accusing the Jewish leadership of converting God’s house of prayer into a den of robbers. Matt. 21:12-13. When he subsequently returned to the Temple courts and began teaching there, the chief priests and elders came to him demanding to know:
By what authority are you doing these things? Who gave you this authority?
Jesus’ answer to this question started with a question: who gave John his authority to baptize? Did God or men authorize him to do this? Matt. 21:24. The Jewish leaders, of course, understood that if they admitted that God sent John, they would also have to admit that God sent Jesus. But they considered it politically unwise to say—in front of a crowd that had believed John—that John was only a self-appointed crackpot (which is what the leaders really believed). So they refused to answer Jesus’ question. Matt. 21:25-27.
It is at this point that Jesus told the parable of the two sons, to bring into clear focus the full implications of the leaders’ attitude. Jesus’ invited his hearers—both the leaders who had come to challenge him and the crowd—to compare themselves to the two sons. The first son was a picture of gross sinners, the kind of people the Jewish leaders rejected, who had believed the preaching of John and changed their lives. These people, like the first son, had at first refused to do what the Father asked, but later changed their minds and did it. The second son is a picture of the religious leaders, who publicly professed their willingness to do what God asked, but then failed to do it. Indeed, even when John came, they did not repent (like the tax collectors and prostitutes did) and believe his message. Therefore, Jesus said that the tax collectors and prostitutes, who listened to God when He spoke through John, would enter into the kingdom of God—where God is king—ahead of them. In this parable, Jesus’ answer to the religious leaders’ question regarding the source of his authority was that the leaders themselves had rejected God’s authority. It was the repentant tax collectors and prostitutes, rather than the unrepentant religious leaders, who ultimately did as God asked them to.
Jesus amplifies this point with his next parable, the wicked tenants (Matt. 21:33-41), then answers the leaders’ question directly with a quotation from Psalm 118:22-23, which, as applied to Jesus, asserted that God had made him the capstone (and, thus, had given him authority to do what he was doing). Jesus then concluded:
Therefore I tell you, the Kingdom of God will be taken away from you, and will be given to a nation producing its fruit. 44 He who falls on this stone will be broken to pieces, but on whomever it will fall, it will scatter him as dust.
Matt. 21:43-44 (WEB). Thus, in this passage, even metamelomai, the weaker verb rendered repent (or change one’s mind), is clearly associated with actions—doing what the Father asks—and with producing fruit.