This Bible contradiction is from the Skeptic's Annotated Bible.
Jesus told his disciples everything.
John 15:15 View context
Henceforth I call you not servants; for the servant knoweth not what his lord doeth: but I have called you friends; for all things that I have heard of my Father I have made known unto you.
There were some things that Jesus didn't tell them.
John 16:12 View context
I have yet many things to say unto you, but ye cannot bear them now.