21:28-32 Parables which give reproof, speak plainly to the offenders, and judge them out of their own mouths. The parable of the two sons sent to work in the vineyard, is to show that those who knew not John's baptism to be of God, were shamed by those who knew it, and owned it. The whole human race are like children whom the Lord has brought up, but they have rebelled against him, only some are more plausible in their disobedience than others. And it often happens, that the daring rebel is brought to repentance and becomes the Lord's servant, while the formalist grows hardened in pride and enmity.
32. For John came unto you in the way of righteousness—that is, calling you to repentance; as Noah is styled "a preacher of righteousness" (2Pe 2:5), when like the Baptist he warned the old world to "flee from the wrath to come."
and ye believed him not—They did not reject him; nay, they "were willing for a season to rejoice in his light" (Joh 5:35); but they would not receive his testimony to Jesus.
but the publicans and the harlots believed him—Of the publicans this is twice expressly recorded, Lu 3:12; 7:29. Of the harlots, then, the same may be taken for granted, though the fact is not expressly recorded. These outcasts gladly believed the testimony of John to the coming Saviour, and so hastened to Jesus when He came. See Lu 7:37; 15:1, &c.
and ye, when ye had seen it, repented not afterward, that ye might believe him—Instead of being "provoked to jealousy" by their example, ye have seen them flocking to the Saviour and getting to heaven, unmoved.
Parable of the Wicked Husbandmen (Mt 21:33-46).