Passage
And he answereth them and saith, O faithless generation, how long shall I be with you? how long shall I bear with you? bring him unto me.
And he answereth them and saith, O faithless generation, how long shall I be with you? how long shall I bear with you? bring him unto me.
Mark 9:17 And one of the multitude answered him, Teacher, I brought unto thee my son, who hath a dumb spirit;
Mark 9:18 and wheresoever it taketh him, it dasheth him down: and he foameth, and grindeth his teeth, and pineth away: and I spake to thy disciples that they should cast it out; and they were not able.
Mark 9:19 And he answereth them and saith, O faithless generation, how long shall I be with you? how long shall I bear with you? bring him unto me.
Mark 9:20 And they brought him unto him: and when he saw him, straightway the spirit tare him grievously; and he fell on the ground, and wallowed foaming.
Mark 9:21 And he asked his father, How long time is it since this hath come unto him? And he said, From a child.
The verse centers on "faith", "answereth", "saith", "faithless", "generation", "long", and "shall". It is saying that the verse draws attention to "faith" and "answereth", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 18's "and wheresoever it taketh him it dasheth..." into verse 20's "And they brought him unto him and...", so "faith" and "answereth" belong inside that flow. In Mark context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "faith" and "answereth" with trust shaped by these words, not by a vague optimism outside the passage.