Passage
No longer do I call you servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I heard from my Father, I have made known unto you.
John 15:15 (ASV)
Nearby Context
John 15:13 Greater love hath no man than this, that a man lay down his life for his friends.
John 15:14 Ye are my friends, if ye do the things which I command you.
John 15:15 No longer do I call you servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I heard from my Father, I have made known unto you.
John 15:16 Ye did not choose me, but I chose you, and appointed you, that ye should go and bear fruit, and [that] your fruit should abide: that whatsoever ye shall ask of the Father in my name, he may give it you.
John 15:17 These things I command you, that ye may love one another.
Study Lenses
The verse centers on "all things", "called", "longer", "servants", "knoweth", "lord", and "doeth". It is saying that the verse draws attention to "all things" and "called", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 14's "Ye are my friends if ye do..." into verse 16's "Ye did not choose me but I...", so "all things" and "called" 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 "all things" and "called" with trust shaped by these words, not by a vague optimism outside the passage.