I, Sir. [1] This phrase is borrowed from the Hebrew language; for, when the Hebrews wish to offer their services, and to declare that they are ready to obey, they speak in this manner, "Here I am, Sir," It is a laudable virtue in itself, as soon as God has spoken, to yield to Him ready and cheerful obedience; and Christ does not here give the commendation to slowness. But as both are improper--to delay before doing your duty, and to promise what you do not perform--Christ shows that this hypocrisy is less to be endured than the fierceness which, in process of time, is subdued.

Footnotes

1 - "Seigneur, j'y vay;" -- "Sir, I go to it."

I go, sir - This is all respect, complaisance, and professed, obedience; but he went not: he promised well, but did not perform. What a multitude of such are in the world, professing to know God, but denying him in their works! Alas! what will such professions avail, when God comes to take away the soul?

And he came to the second,.... The Scribes and Pharisees, by the ministry of John the Baptist, Christ, and his apostles also:
and said likewise; the same things as to the other son, the publicans and sinners; calling them into the Gospel dispensation, to hear the word, embrace truth, attend on ordinances, and labour in promoting the kingdom, and interest of the Messiah, whilst they had the light of the Gospel with them. Urging also the relation they stood in to God, as a part of the Jewish body; to whom, among other external privileges, the adoption belonged:
and he answered and said, I go, sir, and went not: the word "go" is not in the generality of the Greek copies; the phrase is only "I sir", though it is rightly enough supplied as to the sense. Beza says, it was in his most ancient copy; and so it is in the Arabic and Persic versions, and in Munster's Hebrew Gospel; though it is not in the Syriac and Ethiopic versions. So, the Scribes and Pharisees seemed pleased with the ministry of John for a while, and at first were forward to submit to his baptism, and were very inquisitive about the Messiah: yet, when he was declared in John's ministry, and by his own doctrine, and miracles, they refused to give in to the belief of him; they would neither enter into the Gospel kingdom, embrace the doctrines, and obey the commands of it themselves, nor suffer others to enter in; but, as much as in them lay, by their reproaches, menaces, and excommunications, deterred them from it. They, were like some other persons, who promise fair, and talk much of doing good works, but do none; teach the people to do them, but do not perform them themselves, though they would seem to do them; make great pretensions to them, boast of them, and trust in them; and therefore, of all men, ought to be careful to maintain them, and yet do the least.

And he came to the second, and said likewise. And he answered and said, I go, sir--"I, sir." The emphatic "I," here, denotes the self-righteous complacency which says, "God, I thank thee that I am not as other men" (Luke 18:11).
and went not--He did not "afterward repent" and refuse to go; for there was here no intention to go. It is the class that "say and do not" (Matthew 23:3) --a falseness more abominable to God, says STIER, than any "I will not."

He answered, I go, sir: but went not - Just so did the scribes and Pharisees: they professed the greatest readiness and zeal in the service of God: but it was bare profession, contradicted by all their actions.