In John 3:16, Jesus refers to himself in third person (grammarically), but elsewhere in scripture, He refers to himself in first person (I come that they may have life...I and the Father are one). Does any one have any ideas on this?
Welcome Mrs D.:
Actually, the Lord Jesus referred to Himself at least as frequently in the third person as in the first. You will notice in John 3:13 & 14 that He calls Himself "the Son of Man", and that was the most frequent title which He gave to Himself. That's because He would be the Man of Sorrows and the Lord would lay upon Him the inquity of us all.
I believe that the Lord Jesus was using this form of speech with Nicodemus in order to teach
"the doctrine of Christ" (2 Jn.9-11) in a formal way, as He also does in John 5 and other Scriptures, and to have us understand that the words He spoke came directly from the Father.
The Lord said in John 7:16: "MY DOCTRINE IS NOT MINE, BUT HIS THAT SENT ME", so as the One who was sent by the Father, He gave us the Father's words concerning the Son, and John testifies in 1 Jn. 5:9: "If we receive the witness of men, the witness of God is greater: for this is the witness of God which He hath testified of His Son".
The doctrine of Christ is the key doctrine of Scripture:
"Whosoever transgresseth, and abideth not in THE DOCTRINE OF CHRIST, hath not God. He that abideth in THE DOCTRINE OF CHRIST, he hath both the Father and the Son. If there come any unto you, and bring not THIS DOCTRINE, receive him not into your house, neither bid him God speed: for he that biddeth him God speed is parkataker of his evil deeds" (2 Jn.9-11.
The doctrine of Christ in a nutshell is that the Son of Man is the Son of God, and the Son of God is fully GOD and fully sinless Man. Theological liberals and many of the cults deny this, and can trace their roots to Gnosticism, which also denied this doctrine.