WNT(i)
17 "Rabbi," answered one of the crowd, "I have brought you my son. He has a dumb spirit in him;
18 and wherever it comes upon him, it dashes him to the ground, and he foams at the mouth and grinds his teeth, and he is pining away. I begged your disciples to expel it, but they had not the power."
19 "O unbelieving generation!" replied Jesus; "how long must I be with you? how long must I have patience with you? Bring the boy to me."
20 So they brought him to Jesus. And the spirit, when he saw Jesus, immediately threw the youth into convulsions, so that he fell on the ground and rolled about, foaming at the mouth.
21 Then Jesus asked the father, "How long has he been like this?" "From early childhood," he said;
22 "and often it has thrown him into the fire or into pools of water to destroy him. But, if you possibly can, have pity on us and help us."