Passage
Verily, verily, I say to you, He that enters not in by the door to the fold of the sheep, but mounts up elsewhere, *he* is a thief and a robber;
Verily, verily, I say to you, He that enters not in by the door to the fold of the sheep, but mounts up elsewhere, *he* is a thief and a robber;
John 10:1 Verily, verily, I say to you, He that enters not in by the door to the fold of the sheep, but mounts up elsewhere, *he* is a thief and a robber;
John 10:2 but he that enters in by the door is [the] shepherd of the sheep.
John 10:3 To him the porter opens; and the sheep hear his voice; and he calls his own sheep by name, and leads them out.
The verse centers on "sheep", "verily", "enters", "door", "fold", "mounts", and "elsewhere". It is saying that the verse draws attention to "sheep" and "verily", so its meaning should be read from those terms before moving to application.
The next verse adds "but he that enters in by the...", so "sheep" and "verily" should be read forward into that movement. 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 "sheep" and "verily" with trust shaped by these words, not by a vague optimism outside the passage.