Does the Bible verify that pig blood was once offered on the altar?
In Isaiah 63:6 the Lord said that when those who are not humble and contrite in spirit, and who don’t tremble at God’s word bring an offering, it’s as it they presented pig’s blood. But the Bible does not make any reference to anyone actually doing this.
However, in the extra-Biblical Book of Maccabees there is a mention of Syrian King Antiochus Epiphanes having the blood of a sacrificed pig sprinkled in the Holy of Holies and on sacred Torah scrolls in an act of blasphemy toward God. This is considered by many to have been an actual event, which led to the Maccabean revolt of 168-165 BC.