Sop
A sop was a piece of bread used to scoop up broth, sauce, or other food from a shared dish — a common practice at meals in the ancient Near East. In Ruth 2:14 Boaz invites Ruth to eat with his reapers and dip her morsel in the vinegar (a sour wine sauce). The most theologically significant use is at the Last Supper, where Jesus took a piece of unleavened bread, dipped it in the dish of bitter herbs at the Passover table, and gave it to Judas Iscariot, identifying him as the betrayer (John 13:26–27).
Giving a sop to a guest was a mark of distinction and honor, making the act of handing it to Judas a final, deliberate gesture of grace extended even to the one who would betray him. After receiving the sop, John records, Satan entered into Judas, and Jesus dismissed him with the words "What thou doest, do quickly."