Hastings' Dictionary of the Bible (1898)
SOP. John 13:26. Our ordinary table-utensils were unknown among the Hebrews. Hence, in eating broth or milk, it was either taken with the hollow of the hand or the bread was dipped into it. This is at present the usage in all the Oriental countries - even at the table of the Persian king. Thus the reapers of Boaz dipped their "morsel in the vinegar," Ruth 2:14, and thus our Saviour "dipped the sop," or morsel, and gave it to the traitor Judas.