Passage
But all things whatsoever John said of this man were true. And many believed n him.
But all things whatsoever John said of this man were true. And many believed n him.
John 10:40 And he went again beyond the Jordan, into that place where John was baptizing first. And there he abode.
John 10:41 And many resorted to him: and they said: John indeed did no sign.
John 10:42 But all things whatsoever John said of this man were true. And many believed n him.
The verse centers on "all things", "whatsoever", "john", "said", "true", and "believed". It is saying that the verse draws attention to "all things" and "whatsoever", so its meaning should be read from those terms before moving to application.
The prior verse says "And many resorted to him and they...", giving immediate footing for "all things" and "whatsoever". In John context, the local focus is the identity of Jesus, new birth, eternal life, and belief and unbelief.
A plain takeaway is to answer the verse's own emphasis on "all things" and "whatsoever" with trust shaped by these words, not by a vague optimism outside the passage.