Answer: Jesus makes known to His followers--His obedient friends--everything that He learned from His Father. Because His true followers are His obedient friends who have been taught by Him everything He learned from His Father, these obedient friends are chosen by Jesus and given an appointment, task, job or work of service to go and bear fruit--fruit that will last, (verses 15 and 16).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
John 8:26: [Jesus said,] "I have much to say in judgment of you. But He Who sent Me is reliable, and what I have heard from Him I tell the world."
John 12:49-50: "For I did not speak of My Own accord, but the Father Who sent Me commanded Me what to say and how to say it. I know that His command leads to eternal life. So whatever I say is just what the Father has told Me to say."