17When evening came, Jesus arrived with the Twelve. 18While they were reclining at the table eating, he said, “I tell you the truth, one of you will betray me—one who is eating with me.”
19They were saddened, and one by one they said to him, “Surely not I?”
20″It is one of the Twelve,” he replied, “one who dips bread into the bowl with me. 21The Son of Man will go just as it is written about him. But woe to that man who betrays the Son of Man! It would be better for him if he had not been born.”
22While they were eating, Jesus took bread, gave thanks and broke it, and gave it to his disciples, saying, “Take it; this is my body.”
In Hebrew tradition, the person leading the feast would dip his bread into the bowl with the person sitting next to him. Judas, sitting next to him, wouldn’t look suspicious, therefore. They were just following custome.
And the amount of times the disciples didn’t understand if Jesus was being symbolic or literal…it’s no surprise they didn’t catch it right away. If they caught it later? The Bible says Judas “quickly left” the room.