1) Frank Pollard gave a sermon based on Mark 9 titled "When It Is Time To Leave the Huddle". He discussed how Jesus, Peter, James, and John had a mountaintop experience but then had to go into the valley to serve others.
2) Jesus, Peter, and John encountered a boy with an unclean spirit that the disciples could not cast out. Jesus cast it out and said "all things are possible for one who believes".
3) Pollard said believers need to have mountaintop experiences with God but also obey their assignment to share the gospel and serve others. Leaving the huddle to fulfill their purpose is more important than just understanding it.