Passage
And Jesus saith to him: If thou canst believe, all things are possible to him that believeth.
And Jesus saith to him: If thou canst believe, all things are possible to him that believeth.
Mark 9:20 And he asked his father: How long time is it since this hath happened unto him? But he sad: From his infancy.
Mark 9:21 And oftentimes hath he cast him into the fire and into the waters to destroy him. But if thou canst do any thing, help us, having compassion on us.
Mark 9:22 And Jesus saith to him: If thou canst believe, all things are possible to him that believeth.
Mark 9:23 And immediately the father of the boy crying out, with tears said: I do believe, Lord. Help my unbelief.
Mark 9:24 And when Jesus saw the multitude running together, he threatened the unclean spirit, saying to him: Deaf and dumb spirit, I command thee, go out of him and enter not any more into him.
The verse centers on "all things", "believeth", "jesus", "saith", "thou", "canst", and "possible". It is saying that the verse draws attention to "all things" and "believeth", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 21's "And oftentimes hath he cast him into..." into verse 23's "And immediately the father of the boy...", so "all things" and "believeth" 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 "all things" and "believeth" with trust shaped by these words, not by a vague optimism outside the passage.