Flatt wrote verses 17-29 was an opportunity for the twelve to learn two lessons from the boy possessed by a demon. The apostles should not have taken the power given them in Mark 3 for granted. They had evidently become self-sufficient and forgotten they must remember to rely on God. This was the reason why they found it impossible to heal the boy themselves.
They also needed to understand that greatness does not lie on the mountain of ceremony, Flatt wrote. After the transfiguration, Peter had wanted to build three tents to honor Moses, Elijah and Christ. Peter’s mind reveals he was still worldly because the worldly mind strives to achieve and live in glory. Jesus, however, reminds us that true greatness is in the valley of need.
This is why Jesus calls to him a child to teach the haughty-minded disciples the blissful youngster is unassuming and innocent, without lofty goals of glory, is humble and dependant.
The child’s mind really defines what the Christian must be. Wouldn’t the world be remarkably different if that were true?