If a man sins against his neighbor, and is made to take an oath, and the oath is made before your altar in this house;
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George Leo Haydock
Altar; thus solemnly consenting to be punished by God, if he swear falsely. (Haydock)
This practice was not prescribed by the law, but took place when witnesses could not be procured, or when it was necessary to rely on the word of the accused.