Mark 9:10

And they kept that saying with themselves, questioning one with another what the rising from the dead should mean.

This saying comes from the transfiguration, when the disciples had been with Christ on the mount while below them were people needing deliverance from Satan through faith and prayer. The events that follow the transfiguration are the same as those recorded in Matthew 17:9-21 and Luke 9:37-45. Jesus had charged the disciples to keep the vision secret until the rising from the dead.

They kept that saying about rising from the dead among themselves, questioning one with another what it should mean, because they did not understand the resurrection. Although Jesus had spoken plainly of what lay ahead, they were slow to understand and did not ask Him to explain it. Sorrow led them to shrink from learning more about a future they hoped would never come.