Jesus says that the One who sent Him is true and that He speaks to the world what He has heard from Him. John then tells the reader explicitly that Jesus' opponents did not understand that He was speaking to them about the Father.
Jesus in Context
The One Who Sent Me Is True
Jesus describes His teaching as the faithful communication of what He has heard from the Father who sent Him, while His opponents fail to understand that He is speaking about the Father.
Introduction
Historical and Cultural Context
Being 'sent' is one of the Gospel of John's recurring ways of describing Jesus' mission. Jesus presents Himself as acting under the commission of the Father. The language of hearing and speaking likewise portrays His teaching as faithfully communicating what comes from the One who sent Him.
The narrator's explanation in John 8:27 gives the reader information that Jesus' opponents do not yet grasp, a literary technique John uses repeatedly.
Why It Matters
The passage emphasizes the claimed divine source of Jesus' message. Jesus does not portray His teaching as an independent human philosophy. He speaks what He has heard from the Father, and the misunderstanding of His hearers again exposes their failure to recognize the relationship at the center of His mission.