Being great is not all about how much energy or power one has, but how much impact one makes to one's life, and the society. In the context of Jesus, greatness is more than one acquires or does for himself, it has to involve others in a apositive way.

YES, caring for a little child is such a big example of being great. Little children need a tender, loving, and compassionate heart. It only takes a great heart to have this. Little children also need a lot of attention, patience, and a care. It takes a great being to have all these, but not how much power, and the greatest of all, only a person with wisdom and understanding can be defined as being great because these are the factors that will inspire anybody to do great things.

Jesus responded by healing the boy, but after acquiring some information about the demon that was troubling the boy.

What does this teach me?

That there are some situations that will not just go because a believer has barked at them, or simply instructed them to go.

That in some cases, one has to first seek the face of God earnestly, for a situation/s to go.

That one must have faith when he/she goes to ask something from God, because without faith not many miracles can be performed. This is the cardinal rule for the people who are in the ministry, or those who wish, or rather feel that they have a calling from God to serve Him. We must learn to believe, thogh it's not easy anyway because some miracles are to hard for a human being to believe that they ca, not until they have been.