Albert Barnes on Matthew 21:28-32

But what think ye? A way of speaking designed to direct them particularly to what he was saying, that they might be self-convicted.

Two sons. By those two sons our Lord intends to represent the conduct of the Jews, and that of the Publicans and sinners.

In my vineyard. Mt 21:33. To work in the vineyard here represents the work which God requires man to do.

I will not. This had been the language of the Publicans and wicked men. They refused at first, and did not profess to be willing to go.

Repented. Changed his mind. Afterwards, at the preaching of John and Christ, the publicans--the wicked--repented, and obeyed.

The second--said, I go, sir: and went not. This represented the conduct of the Scribes and Pharisees--professing to obey God; observing the external rites of religion; but opposed really to the kingdom of God, and about to put his Son to death.

Whether of them twain, etc. Which of the two.

They say unto him, The first. This answer was correct. But it is strange that they did not perceive that it condemned themselves.

Go into the kingdom of God. Become Christians, or more readily follow the Saviour. Mt 3:2.

Before you. Rather than you. They are more likely to do it than you. You are self-righteous, self-willed, and obstinate. Many of them had believed, but you have not. John came unto you in the way of righteousness. That is, in the right way, or teaching the way to be righteous; to wit, by repentance. Publicans and harlots heard him, and became righteous, but they did not. They saw it, but, as in a thousand other cases, it did not produce the proper effect on them, and they would not repent.