Early in the ministry of Jesus, certain Greeks desired Philip to bring them to see Jesus. Before them all Jesus began to pray: My soul is troubled; Father, save me from this hour: but for this reason I came and am facing this hour. Father, glorify thy name. Then there came a voice from heaven, saying, I have both glorified it, and will glorify it again. The people that stood by heard the voice but said it must be thunder. Jesus answered and said, This voice came not because of me, but for your sake.
And I, if I be lifted up from the earth, will draw all men unto me. This he said, signifying what death he should die.
Jesus told Peter that he was listening to the wrong voice and it was time for them all to begin to understand the Big picture of God's eternal plan of salvation.
Jesus even mentioned the cross as he shared: from Marks's Gospel chapter 8; Whosoever will come after me, let him deny himself, and take up his cross, and follow me. For what shall it profit a man, if he shall gain the whole world, and lose his own soul? Or what shall a man give in exchange for his soul?
A few days later as they passed through Galilee; Jesus the second time, again taught his disciples about his death, and said to them, The Son of man is soon to be delivered into the hands of men, and they shall kill him; and after that he is killed, he shall rise the third day. But they did not understand his saying, and were afraid to ask him.
You would think the followers of Jesus might get a clue after being told twice that he was about to be betrayed, killed and rise again, but no they were dense and a third time Jesus attempted to help them to understand as they went up to Jerusalem.
Jesus continued saying; These things have I spoken unto you, while I am still here with you. But I will not leaved you comfortless, For the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, what ever I have said unto you.