12 'If one carries holy flesh in the skirt of his garment, and touches with his skirt bread, or pottage, or wine, or oil, or any kind of food, does it become holy?'" The priests answered, "No." 13 Then said Haggai, "If one who is unclean by contact with a dead body touches any of these, does it become unclean?" The priests answered, "It does become unclean." 14 Then Haggai said, "So is it with this people, and with this nation before me, says the Lord; and so with every work of their hands; and what they offer there is unclean.
Matthew Henry's Commentary on Haggai 2:12-14
Commentary on Haggai 2:10-19
(Read Haggai 2:10-19)
Many spoiled this good work, by going about it with unholy hearts and hands, and were likely to gain no advantage by it. The sum of these two rules of the law is, that sin is more easily learned from others than holiness. The impurity of their hearts and lives shall make the work of their hands, and all their offerings, unclean before God. The case is the same with us. When employed in any good work, we should watch over ourselves, lest we render it unclean by our corruptions. When we begin to make conscience of duty to God, we may expect his blessing; and whoso is wise will understand the loving-kindness of the Lord. God will curse the blessings of the wicked, and make bitter the prosperity of the careless; but he will sweeten the cup of affliction to those who diligently serve him.