But no one at the table knew why Jesus had said this to him.

John 13:27
And when Judas had taken the morsel, Satan entered into him. Then Jesus said to Judas, "What you are about to do, do quickly."

John 13:29
Since Judas kept the money bag, some thought that Jesus was telling him to buy what was needed for the feast, or to give something to the poor.

Now no man at the table knew for what intent he spoke this to him.