“The next day, when they came down from the mountain, a large crowd met him. A man in the crowd called out, “Teacher, I beg you to look at my son, for he is my only child. A spirit seizes him and he suddenly screams; it throws him into 
 convulsions so that he foams at the mouth. It scarcely ever leaves him and is 
 destroying him. I begged your disciples to drive it out, but they could not.”

“O unbelieving and perverse generation,” Jesus replied, “how long shall I stay with you and put up with you? Bring your son here.”

Even while the boy was coming, the demon threw him to the ground in a
 convulsion. But Jesus rebuked the impure spirit, healed the boy and gave him back to his father. And they were all amazed at the greatness of God.” - Luke 9: 37 - 43