John leaned in order to ask Jesus who was the betrayer. Can you imagine the response the disciples would have had if they knew it was Judas Iscariot? There would have been a killing if they found out who the betrayer was. Giving the morsel (sop) to Judas was an uncaught sign of recognition to John. Some commentators say it was the Lord’s final extension of grace to Judas. If this is so, Judas deliberately rejected the extension of mercy to him. Giving Judas a morsel of bread was a sign of friendship. The Bible Knowledge Commentary states that it is ironic that Jesus’ act of friendship to Judas signals Judas’ betrayal of friendship.
After this, Satan enters into Judas. (v. 2). This is one of the most terrible expressions in the Scriptures. Judas became Satan’s tool against Jesus. Jesus tells Judas to do the act quickly. This may speak to the time of God’s proper timing.
No one grasped the meaning of Jesus’ action and words to Judas. Nobody caught what was being said and done. They assumed that he, the group’s treasurer, was going to purchase food for the Passover feast. They could have also thought that he was going to give some money to the poor. He had deceived the disciples, but not Jesus. It can be said that since it was night time, Judas was leaving the Light to go into darkness. This would be a symbolic significance. Note John 8:12; 12:35, 46. The darkness of sin. John 3:19.