It can be easy for us to overlook the advantage we have in living after the resurrection of Christ. We know how the story ends. We may recoil in horror that Jesus would be handed over to sinners, but it does not shake our faith. That is because we have a picture of God’s plan and all that Jesus accomplished that is fuller than the one people had before they saw Christ raised from the dead.
With that in mind, consider what the disciples would have thought when they heard that one of them would betray Christ (John 13:18). Seeing one of their own betray our Savior might cause a crisis of faith. It is possible they might ask if they had been fooled into following a false teacher if one of the men who was closest to Jesus could turn on Him. They might have wondered how much control Jesus had over His circumstances if one of their brothers could betray Him.
Jesus knew His betrayal might spark a crisis of faith among His disciples, and He forewarned them about it so that they would know who He was (v. 19). Jesus was saying that His prediction of His betrayal would prove He was not at the mercy of His betrayer, that the disciples would see Him being handed over to the authorities and remember that Jesus saw it coming. Despite the awfulness of the news, telling them about it beforehand would finally strengthen their faith.
Judas’ betrayal of Jesus would also fulfill the Scriptures (v. 18). Jesus quotes Psalm 41:9, where David complains that one of his meal companions lifted up his heel against him. In the ancient Near East, to eat a meal with someone was a sign of friendship and trust, so it was especially terrible for someone who sat at your table to betray you. David was the greatest king of ancient Israel, so the psalm indicates that his betrayal was not incompatible with his position. The same is true of Jesus. He would be betrayed, but that would not make Him any less the King. Moreover, Psalm 41 also predicts the final triumph of David over his enemies. By quoting the psalm, Jesus indicated that despite His betrayal, He would have the ultimate victory over His betrayers.
To reject Jesus as Judas did was really to reject God, for to receive Jesus is really to receive God as Lord (John 12:44). Jesus said a similar relationship exists between how people receive us and how they receive God (13:20). When people receive Christians and the gospel they preach, they receive Christ, and in receiving Christ, they receive God. People might reject us in a manner similar to how Judas rejected Jesus, but ultimately they are rejecting God.