What does Matthew 26:31 mean?

Then Jesus told them, 'Tonight, every one of you is going to lose faith in me. It's like what was written: "I will strike down the shepherd, and the sheep will scatter."' Matthew 26:31 - Modern Text Bible

(Jesus warns his closest friends that they're all about to abandon him, just as the ancient scriptures predicted. He's preparing them for the shock of their own failure.)