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. And now, I pray you, consider from this day and backward, before a stone was laid upon a stone in the temple of Jehovah."

Thus, Haggai applied the analogy we have already discussed under the previous verses. Yes, the altar they had erected upon the original site, in conformity to God's law, was "holy", but the sinful nation (continuing in their neglect of sacred duty) were unholy still, and, therefore, the very sacrifices they offered were themselves unholy through contamination by contact with the sinful nation. The sinful nation would have to make some changes before blessings could be bestowed.

"Consider from this day and backward ..." This was a call for the people to look back over the past fourteen years of their shameful neglect of the principal purpose for which they had been allowed by the Father to return to their homeland, and to observe the stark lack of God's blessing. He then proceeded to specify exactly what had been taking place. Why had not God blessed them? The whole nation was defiled through their long neglect of sacred duty and the two generations of contact with Babylonian paganism.