Passage
They vnderstoode not that hee spake to them of the Father.
John 8:27 (GNV)
Nearby Context
John 8:25 Then saide they vnto him, Who art thou? And Iesus saide vnto them, Euen the same thing that I said vnto you from the beginning.
John 8:26 I haue many things to say, and to iudge of you: but he that sent me, is true, and the things that I haue heard of him, those speake I to the world.
John 8:27 They vnderstoode not that hee spake to them of the Father.
John 8:28 Then said Iesus vnto them, When ye haue lift vp the Sonne of man, then shall ye know that I am he, and that I doe nothing of my selfe, but as my Father hath taught me, so I speake these things.
John 8:29 For he that sent me, is with me: the Father hath not left me alone, because I do alwayes those things that please him.
Study Lenses
The verse centers on "vnderstoode", "spake", and "father". It is saying that the verse draws attention to "vnderstoode" and "spake", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 26's "I haue many things to say and..." into verse 28's "Then said Iesus vnto them When ye...", so "vnderstoode" 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 "vnderstoode" and "spake" with trust shaped by these words, not by a vague optimism outside the passage.