John Gill Commentary Haggai 2:14

"Then answered Haggai and said, So is this people, and so is this nation before me, saith Jehovah; and so is every work of their hands; and that which they offer there is unclean." — Haggai 2:14 (ASV)

Then answered Haggai, and said
To the priests, and before the people; and made an application of these things to them, which was the thing in view in putting the questions: So is this people, and so is this nation before me, says the
Lord ; not only those people that were present and at work at the temple, but those that were absent, even the whole body of the people; who, though they were pure in their own eyes, yet were not so before the Lord; who knew their hearts, and the spring of all their actions; what were their ends and views in all they did:

as a garment carrying in it holy flesh could not sanctify other things touched by it that were common and profane, but left them as they were; so their ritual devotions, and externally holy actions, did not and could not sanctify their impure hearts, but left them as unclean as before; nor did they sanctify their common mercies, their bread, pottage, wine, and oil: and, on the other hand, as an impure person made everything impure he touched; so they, being impure in heart, all their actions, even their religious ones, were impure also, as follows:

and so is every work of their hands; and that which they offer
there is unclean ; pointing at the altar, which they had built, and offered sacrifice on ever since they came out of Babylon, though the temple was not yet built, (Ezra 3:3–6) but all their outward religious services, and all the sacrifices they offered up, were in the Lord's account impure and abominable, as well as themselves; coming from an unsanctified heart, and offered up with unclean hands, and without repentance towards God, and faith in Christ; and living in other respects in disobedience to God, and especially while they neglected the building of the temple; satisfying themselves with offering sacrifices on the altar, when the house of God lay desolate; which is the principal thing respected, as appears by what follows.