After Jesus had gone into the house, His disciples asked Him privately, “Why couldn’t we drive it out?”
Textus Receptus (TR) - Mark 9:28 >Καὶ εἰσελθόντα αὐτὸν εἰς οἶκον, οἱ μαθηταὶ αὐτοῦ ἐπηρώτων αὐτὸν κατ᾿ ἰδίαν ὅτι Ἡμεῖς οὐκ ἠδυνήθημεν ἐκβαλεῖν αὐτό;