What does Mark 14:49 mean?

If the world were the least bit righteous, none of this should happen. Jesus should not be betrayed by a thief who claims to be His disciple. If the Sanhedrin truly believed Jesus' teaching was blasphemous, they should have arrested Him while He was teaching. Jesus' more devoted followers should have the integrity to acknowledge their loyalty to Him instead of fleeing into the night and denying Him. And Jesus, the only sinless Man, should never have had to take our sins. But behind the logic of the situation's "should," Jesus made a choice before the world was formed that this would happen.

The Scriptures that Jesus is referring to include a few passages from the Old Testament, primarily, the Suffering Servant of Isaiah 53. The chapter prophetically covers Jesus' rejection, sorrow, grief, and affliction. It mentions how He was pierced with the nails on the cross and abandoned by those who should follow Him. It likens Him to the Passover lamb and prophesies His silence before King Herod. It even predicts that He will be buried in a rich man's grave. But Isaiah 53 also notes that God will be satisfied by Jesus' sacrifice. By bearing our iniquities, Jesus allows us to be accounted righteous.

The immediate Scripture that is fulfilled here was written by David in Psalm 55:12–14. Like David, Jesus is betrayed by a companion, a friend with whom He walked in God's house. The ultimate prophecy that Jesus is looking forward to is that Satan's head will be crushed (Genesis 3:15), and we will be freed.