Mark 9:17
A man in the crowd answered: teacher, I brought you my son, who is possessed by a spirit that has robbed him of speech — the father's report begins with the possession's specific effect: a spirit that has robbed him of speech (alalon pneuma, a mute spirit). The son cannot speak because the spirit has taken away his speech. The father brought his son to Jesus directly but found the disciples instead, and the disciples have failed.