Passage
This parable spake Iesus vnto them: but they vnderstoode not what things they were which he spake vnto them.
John 10:6 (GNV)
Nearby Context
John 10:4 And when hee hath sent foorth his owne sheepe, he goeth before them, and the sheepe follow him: for they know his voyce.
John 10:5 And they will not follow a stranger, but they flee from him: for they know not the voyce of strangers.
John 10:6 This parable spake Iesus vnto them: but they vnderstoode not what things they were which he spake vnto them.
John 10:7 Then sayd Iesus vnto them againe, Verely, verely I say vnto you, I am that doore of the sheepe.
John 10:8 All, that euer came before me, are theeues and robbers: but the sheepe did not heare them.
Study Lenses
The verse centers on "parable", "spake", "iesus", "vnto", "vnderstoode", and "things". It is saying that the verse draws attention to "parable" and "spake", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 5's "And they will not follow a stranger..." into verse 7's "Then sayd Iesus vnto them againe Verely...", so "parable" and "spake" belong inside that flow. 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 "parable" and "spake" with trust shaped by these words, not by a vague optimism outside the passage.