Passage
And ye shall witnesse also, because ye haue bene with me from the beginning.
And ye shall witnesse also, because ye haue bene with me from the beginning.
John 15:25 But it is that the worde might be fulfilled, that is written in their Lawe, They hated me without a cause.
John 15:26 But when that Comforter shall come, whom I will send vnto you from the Father, euen the Spirit of trueth, which proceedeth of the Father, he shall testifie of me.
John 15:27 And ye shall witnesse also, because ye haue bene with me from the beginning.
The verse centers on "shall", "witnesse", "haue", "bene", and "beginning". It is saying that the verse draws attention to "shall" and "witnesse", so its meaning should be read from those terms before moving to application.
The prior verse says "But when that Comforter shall come whom...", giving immediate footing for "shall" and "witnesse". 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 "shall" and "witnesse" with trust shaped by these words, not by a vague optimism outside the passage.