Then the word of the LORD Almighty came to me: “Ask all the people of the land and the priests, ‘When you fasted and mourned in the fifth and seventh months for the past seventy years, was it really for me that you fasted? And when you were eating and drinking, were you not just feasting for yourselves?’” (Zech 7:4–6)

John Calvin, Commentaries on the Twelve Minor Prophets (translated by John Owen), 5:172–73 (formatting added):

God reproved the Jews, who had returned to their own country, for ingratitude, as they had already begun to pollute themselves.

He therefore brings this charge against them,

Have ye fasted to me? have ye eaten to me?

as though he had said,

“God regards not fastings, except they proceed from a sincere feeling and tend to a right and lawful end.”

It was then the object of the Prophet to awaken the Jews, that they might not imagine that God was pacified by fasting or by any other frigid ceremonies, but that they might know that something more was required.

And we see how prone mankind are to rely on external rites, and to think that they have rightly performed their duty to God when they have fasted. As then human nature labours under this disease, the Prophet is here sent to dissipate this delusion; which he does by declaring that fasting does not please God, or is acceptable to him, as though it were something meritorious, or as though there was in it any holiness.

As Calvin says, I am still infected with this disease and believe this lie.

This reminds me of

1. how other OT prophets explain that God hates heartless religion (e.g., Isa 1:10–11; 58:3–6; Jer 7; Joel 2:12–13; Mic 6:6–8).
2. how Jesus contrasts a Pharisee with a tax collector in Luke 18:9–14.
3. how Tim Keller profiles “elder brother” types in The Prodigal God: Recovering the Heart of the Christian Faith . (Cf. my review and the corresponding DVD .)
4. the mindset of a legalist.