When evening had come, He sat down with the twelve. Now as they were eating, He said, “Assuredly, I say to you, one of you will betray Me.” And they were exceedingly sorrowful, and each of them began to say to Him, “Lord, is it I?” He answered and said, “He who dipped his hand with Me in the dish will betray Me. The Son of Man indeed goes just as it is written of Him, but woe to that man by whom the Son of Man is betrayed! It would have been good for that man if he had not been born.” Then Judas, who was betraying Him, answered and said, “Rabbi, is it I?” He said to him, “You have said it.” – Matthew 26:20-25
For about 3.5 years, Jesus had a disciple He knew would betray Him. But He still allowed Judas Iscariot to hang around. Jesus knew it was the order of His Father in heaven to have someone in his company that would be a part of His death on the cross. Judas ate with Jesus, slept under the same stars with Jesus and was just as much part of Jesus’ life as the other disciples.