Called To A Crucified Life
Put yourself in the disciple's shoes for a moment: Jesus had just said to you that He is going to build His Church and that the gates of Hades (the power of death) will not prevail against it. Now He tells you that He is going to be killed and raised up on the third day. No doubt, there was a good bit of confusion on their part.
But it is what He said next, that must have challenged their thinking even more. No He tells them that in order to come after Him, they must deny themselves and take up their cross daily to follow Him.