Albert Barnes Commentary Mark 9:22

"And oft-times it hath cast him both into the fire and into the waters, to destroy him: but if thou canst do anything, have compassion on us, and help us." — Mark 9:22 (ASV)

If thou canst do any thing. I have brought him to the disciples, and they could not help him. If THOU canst do anything, have compassion, etc.