Bede the Venerable — as excerpted in the Catena Aurea on Mark 9:14-29

“(ubi sup.) Again, in a mystical sense, on high the Lord unfolds the mysteries of the kingdom to His disciples, but below He rebukes the multitude for their sins of unfaithfulness, and expels devils from those, who are vexed by them. Those who are still carnal and foolish, He strengthens, teaches, punishes, whilst He more freely instructs the perfect concerning the things of eternity.”