The disciples really didn’t know what was coming. After the crucifixion – and even shortly after the resurrection had already taken place – they still didn’t understand.
But Jesus knew all along. He saw into the glory of eternity. He saw every failure and victory in the history of the church. He saw you and me right now. He saw the resurrection and He no doubt saw the cross. And this is how he began His prayer – knowing that trials and suffering and death were the first things on His agenda:
Jesus spoke these words, lifted up His eyes to heaven, and said: ‘Father, the hour has come. Glorify Your Son, that Your Son also may glorify You, as You have given Him authority over all flesh, that He should give eternal life to as many as You have given Him. And this is eternal life, that they may know You, the only true God, and Jesus Christ whom You have sent. I have glorified You on the earth. I have finished the work which You have given Me to do. And now, O Father, glorify Me together with Yourself, with the glory which I had with You before the world was.'” – John 17:1-5 (NKJV)