Mark 9:28

28 And when he was entered into the house, his disciples asked him privately, Wherefore could not *we* cast him out?

Mark 9:28 Meaning and Commentary

Mark 9:28

And when he was come into the house
Perhaps into the man's house whose child he had healed, or into some other in these parts, for the sake both of retirement and refreshment:

his disciples asked him privately, why could not we cast him out?
The nine disciples, who were particularly concerned in this matter, fearing they had lost the power of casting out devils, conferred upon them, inquired of Jesus, when he was alone, why they could not cast the demon out of the child, when they had ejected unclean spirits out of many others; (See Gill on Matthew 17:19).

Mark 9:28 In-Context

26 And having cried out and torn [him] much, he came out; and he became as if dead, so that the most said, He is dead.
27 But Jesus, having taken hold of him by the hand, lifted him up, and he arose.
28 And when he was entered into the house, his disciples asked him privately, Wherefore could not *we* cast him out?
29 And he said to them, This kind can go out by nothing but by prayer and fasting.
30 And going forth from thence they went through Galilee; and he would not that any one knew it;
The Darby Translation is in the public domain.