We should understand the meaning of "fall away" (Gr. skandalisthesesthe, cf. Mark 4:17; Mark 6:3; Mark 9:42-47) in the light of the prophecy that Jesus said predicted it ( Zechariah 13:7). Zechariah did not mean that the sheep would abandon the shepherd permanently much less that they would cease to be what they were. He pictured the flock fleeing from the shepherd because someone attacked him. That is precisely what the disciples did when the authorities arrested and executed Jesus. Later those sheep rallied around the Shepherd. Jesus announced His leading them as a shepherd to Galilee later ( Mark 14:28). Again He spoke of His resurrection immediately after announcing His death ( Mark 14:24-25). [source][source][source]
Jesus attributed the Shepherd"s striking to God. He changed the Zechariah passage slightly. Clearly Jesus viewed Himself as God"s Suffering Servant ( Isaiah 53:4-6). This point would have helped the disciples accept Jesus" fate. [source][source][source]