He claimed that he would die and come back to life
John 10:17 "Just as the Father knows me and I know the Father--and I lay down my life for the sheep. The reason my Father loves me is that I lay down my life--only to take it up again. No one takes it from me, but I lay it down of my own accord. I have authority to lay it down and authority to take it up again. This command I received from my Father."
John 12:32-33 "'But I, when I am lifted up from the earth, will draw all men to myself.' He said this to show the kind of death he was going to die."
John 16:16 "In a little while you will see me no more, and then after a little while you will see me."
Luke 18:31-33 "Jesus took the Twelve aside and told them, 'We are going up into Jerusalem, and everything that is written by the prophets about the Son of Man will be fulfilled. He will be handed over to the Gentiles. They will mock him, insult him, spit on him, flog him and kill him. On the third day he will rise again.'"