But what think ye? A certain man, &c.— Because the chief priests and elders had said that they did not know whence John's baptism was, Jesus sharply rebuked them for disbelieving him: he conveyed his reproof under the parable of two sons, who were commanded to work in their father's vineyard; and by asking their opinion of the behaviour of these sons, he made them condemn themselves. See on ch. Matthew 13:3. The temper and behaviour of the second son was an exact picture of the temper and behaviour of the Pharisees; for, in their prayers and praises, they gave God the most honourable titles, and professed the utmost zeal to serve him; but at the same time would do no part of the work which he enjoined them, and particularly would not hearken to the Baptist's exhortations. In the character of the other son, the disposition of the tax-gatherers and harlots is well described: they neither professed nor promised to do the will of God; yet, when they came to think seriously, they submitted themselves first to John, then to Christ, and, in consequence of their faith, were admitted to partake of the privileges of the Gospel. See Macknight and Chemnitz.
Related Commentaries of Matthew 21:28
Matthew 21:28-30
28 But what think ye? A certain man had two sons; and he came to the first, and said, Son, go work to day in my vineyard.
29 He answered and said, I will not: but afterward he repented, and went.
30 And he came to the second, and said likewise. And he answered and said, I go, sir: and went not.