'Altar' in the Bible

You are presenting defiled food upon My altar. But you say, ‘How have we defiled You?’ By thinking that the table of the Lord is contemptible and may be despised.

“Oh, that there were even one among you [whose duty it is to minister to Me] who would shut the gates, so that you would not kindle fire on My altar uselessly [with an empty, worthless pretense]! I am not pleased with you,” says the Lord of hosts, “nor will I accept an offering from your hand.

This is another thing you do: you cover the altar of the Lord with tears, with [your own] weeping and sighing, because the Lord no longer regards your offering or accepts it with favor from your hand.