Answer: Jesus, also called here "God the One and Only," made God the Father known to mankind, (verse 18).
MORE INFORMATION AND/OR OTHER SCRIPTURE REFERENCES:
John 3:16-18: [Jesus said,] "For God so loved the world that He gave His One and Only Son, that whoever believes in Him shall not perish but have eternal life. For God did not send His Son into the world to condemn the world, but to save the world through Him. Whoever believes in Him is not condemned, but whoever does not believe stands condemned already because he has not believed in the Name of God's One and Only Son."
John 14:7-10: [Jesus said,] "‘If you really knew Me, you would know My Father as well. From now on, you do know Him and have seen Him.' Philip said, ‘Lord, show us the Father and that will be enough for us.' Jesus answered: ‘Don't you know Me, Philip, even after I have been among you such a long time? Anyone who has seen Me has seen the Father. How can you say, "Show us the Father"? Don't you believe that I am in the Father, and that the Father is in Me? The Words I say to you are not just My Own. Rather, it is the Father, living in Me, Who is doing His work.'"
1 John 4:9: "This is how God showed His love among us: He sent His One and Only Son into the world that we might live through Him."
