Then saith one of his disciples
 Who had no true love for his master, was an hypocrite, and a covetous person: 
 Judas Iscariot;
 so called, to distinguish him from another Judas, an apostle; (See Gill on Matthew 10:4). 
 Simon's [son];
 this is omitted in the Vulgate Latin, Syriac, Persic, and Ethiopic versions; (See Gill on John 13:2); 
 which should betray him;
 and so he did; this was pre-determined by God, foretold in prophecy, and foreknown by Christ; and is observed here, to show the temper and character of the man.