Charles Spurgeon Commentary Matthew 21:30

"And he came to the second, and said likewise. And he answered and said, I [go], sir: and went not." — Matthew 21:30 (ASV)

The second son was of a milder mood and gentler manner. To him the father spoke as to the elder, and the reply was verbally all that he could desire: “I go, sir.” As if it were a matter of course, with exemplary politeness, he assured his father that he was fully at his disposal. He assented and consented. He was orthodox and precise. He had an easy, natural religiousness, which strongly contrasted with the blunt ungodliness of his brother.

But note those words, and went not. His fine phrases and fair promises were deceit and falsehood. He never went to the vineyard, much less lifted pruning-knife or spade. His father’s vineyard might go to ruin for all he cared, yet all the while he was bowing and scraping, and promising what he never meant to perform.