Passage
Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come.
John 16:13 (KJV)
Nearby Context
John 16:11 Of judgment, because the prince of this world is judged.
John 16:12 I have yet many things to say unto you, but ye cannot bear them now.
John 16:13 Howbeit when he, the Spirit of truth, is come, he will guide you into all truth: for he shall not speak of himself; but whatsoever he shall hear, that shall he speak: and he will shew you things to come.
John 16:14 He shall glorify me: for he shall receive of mine, and shall shew it unto you.
John 16:15 All things that the Father hath are mine: therefore said I, that he shall take of mine, and shall shew it unto you.
Study Lenses
The verse centers on "Spirit", "howbeit", "truth", "come", "guide", "shall", and "speak". It is saying that the verse draws attention to "Spirit" and "howbeit", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 12's "I have yet many things to say..." into verse 14's "He shall glorify me for he shall...", so "Spirit" and "howbeit" 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 "Spirit" and "howbeit" with trust shaped by these words, not by a vague optimism outside the passage.