Passage
No longer do I call you slaves, for the slave does not know what his master is doing; but I have called you friends, for all things that I have heard from My Father I have made known to you.
John 15:15 (LSB)
Nearby Context
John 15:13 Greater love has no one than this, that one lay down his life for his friends.
John 15:14 You are My friends if you do what I command you.
John 15:15 No longer do I call you slaves, for the slave does not know what his master is doing; but I have called you friends, for all things that I have heard from My Father I have made known to you.
John 15:16 You did not choose Me but I chose you, and appointed you that you would go and bear fruit, and that your fruit would abide, so that whatever you ask of the Father in My name He may give to you.
John 15:17 This I command you, that you love one another.
Study Lenses
The verse centers on "all things", "called", "longer", "slaves", "does", "master", and "doing". 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 "You are My friends if you do..." into verse 16's "You 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.