SEV Biblia, Chapter 9:28
Y como l entr en casa, sus discípulos le preguntaron aparte: ¿Por qu nosotros no pudimos echarle fuera?
John Gill's Bible Commentary
Ver. 28. And when he was come into the house , etc..] 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).
Matthew Henry Commentary
Verses 14-29 - The father of the suffering youth reflected on the want of power in the disciples; but Christ will have him reckon the disappointment to the want of faith. Very much is promised to our believing. If thou cans believe, it is possible that thy hard heart may be softened, the spiritual diseases may be cured; and, weak as thou art, thou mayest be able to hold out to the end. Those that complain of unbelief, must loo up to Christ for grace to help them against it, and his grace will be sufficient for them. Whom Christ cures, he cures effectually. But Sata is unwilling to be driven from those that have been long his slaves and, when he cannot deceive or destroy the sinner, he will cause his all the terror that he can. The disciples must not think to do their work always with the same ease; some services call for more tha ordinary pains.
Greek Textus Receptus
και 2532 CONJ εισελθοντα 1525 5631 V-2AAP-ASM αυτον 846 P-ASM εις 1519 PREP οικον 3624 N-ASM οι 3588 T-NPM μαθηται 3101 N-NPM αυτου 846 P-GSM επηρωτων 1905 5707 V-IAI-3P αυτον 846 P-ASM κατ 2596 PREP ιδιαν 2398 A-ASF οτι 3754 CONJ ημεις 2249 P-1NP ουκ 3756 PRT-N ηδυνηθημεν 1410 5675 V-AOI-1P-ATT εκβαλειν 1544 5629 V-2AAN αυτο 846 P-ASN
Robertson's NT Word Studies
9:28 {Privately, saying} (kat' idian hoti). Indoors the nine disciples seek an explanation for their colossal failure. They had cast out demons and wrought cures before. The Revisers are here puzzled over Mark's use of hoti as an interrogative particle meaning {why} where #Mt 17:19 has dia ti. Some of the manuscripts have dia ti here in #Mr 9:28 as all do in #Mt 17:19. See also #Mr 2:16 and #9:11. It is probable that in these examples hoti really means {why}. See Robertson, _Grammar_, p. 730. The use of hos as interrogative "is by no means rare in the late Greek" (Deissmann, _Light from the Ancient East_, p. 126).
