Isaiah 64:4
For since the beginning of the world Men have not heard nor perceived by the ear, Nor has the eye seen any God besides You, Who acts for the one who waits for Him.

John 1:18
No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, He has declared Him.

1 John 4:12
[ Seeing God Through Love ] No one has seen God at any time. If we love one another, God abides in us, and His love has been perfected in us.

John 14:7
“If you had known Me, you would have known My Father also; and from now on you know Him and have seen Him.”

Did John the Baptist hear Gods voice ?

Matthew 3:16-17New King James Version (NKJV)
16 When He had been baptized, Jesus came up immediately from the water; and behold, the heavens were opened to Him, and He[a] saw the Spirit of God descending like a dove and alighting upon Him. 17 And suddenly a voice came from heaven, saying, “This is My beloved Son, in whom I am well pleased!  Mark 1:11 Then a voice came from heaven, “You are My beloved Son, in whom I am well pleased.”

Peter, James, John heard!

Jesus Transfigured on the Mount
Matt.17:1-5  Now after six days Jesus took Peter, James, and John his brother, led them up on a high mountain by themselves; 2 and He was transfigured before them. His face shone like the sun, and His clothes became as white as the light. 3 And behold, Moses and Elijah appeared to them, talking with Him. 4 Then Peter answered and said to Jesus, “Lord, it is good for us to be here; if You wish, let us[a] make here three tabernacles: one for You, one for Moses, and one for Elijah.”
5 While he was still speaking, behold, a bright cloud overshadowed them; and suddenly a voice came out of the cloud, saying, “This is My beloved Son, in whom I am well pleased. Hear Him!”  Was John referring to a Physical hearing and seeing in John 5:37 ? Richard Fix http://www.israelofgod.org has and excellent paper on this SEEN an Heard topic which I am paraphrasing in this article.

3 John 1:11 Beloved, do not imitate what is evil, but what is good. He who does good is of God, but[a] he who does evil has not seen God. Equating seeing or not seeing to being Good verses Evil. Is this Literal here? Context, and audience, and Literal or figurative must be considered in bible study. Jesus was directing his comments to non believing Jews.

Strong’s Greek Concordance 3708 The word “Seen”

to see with the eyes
to see with the mind, to perceive, know
to see, i.e. become acquainted with by experience, to experience
to see, to look to
to take heed, beware
to care for, pay heed to
I was seen, showed myself, appeared

John 6:46 (NKJV)
46 Not that anyone has seen the Father, except He who is from God; He has seen the Father.    So John here says that the converted ones See, Preceive God

You can read much more on this verse just remember you can’t use a verse that isn’t understood to make doctrinal positions