John 8:58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am.
The Greek words translated ‘I am’ are ‘ego eimi’
These same words are translated as follows:
John 8:24 I said therefore unto you, that ye shall die in your sins: for if ye believe not that I am (ego eimi) he, ye shall die in your sins.
John 8:28 Then said Jesus unto them, When ye have lifted up the Son of man, then shall ye know that I am (ego eimi) he, and that I do nothing of myself; but as my Father hath taught me, I speak these things.
John 13:19 Now I tell you before it come, that, when it is come to pass, ye may believe that I am (ego eimi) he.
In each of these cases the 'he' is supplied by the translators to make sense in English.
For this reason, it appears in the KJV in italics.
The ‘I am he’ refers in each case to the one that should come according to the prophets.
John denied being ‘he’ – the one expected.
Acts 13:25 And as John fulfilled his course, he said, Whom think ye that I am? I am not he. But, behold, there cometh one after me, whose shoes of his feet I am not worthy to loose.
John sent his disciples to ask this question
Matthew 11:3 And said unto him, Art thou he that should come, or do we look for another?
Luke 7:19 And John calling unto him two of his disciples sent them to Jesus, saying, Art thou he that should come? or look we for another? 20 When the men were come unto him, they said, John Baptist hath sent us unto thee, saying, Art thou he that should come? or look we for another?
‘He that should come’ is the one of whom Moses wrote.
Deuteronomy 18:18 I will raise them up a Prophet from among their brethren, like unto thee, and will put my words in his mouth; and he shall speak unto them all that I shall command him. 19 And it shall come to pass, that whosoever will not hearken unto my words which he shall speak in my name, I will require it of him.
Philip uses a similar phrase:
John 1:45 Philip findeth Nathanael, and saith unto him, We have found him, of whom Moses in the law, and the prophets, did write, Jesus of Nazareth, the son of Joseph.
The ‘he’ promised was the redeemer who was prophesied before Abraham was born.
He appears as the seed of the woman in the curse upon the serpent in Eden.
Genesis 3:15 And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
This being the case, Jesus was prophesied before Abraham was born.
Abraham 'saw his day' with the eye of faith.
In scripture he was before Abraham in time (though not in the sense of pre-existing).
Also, he was before Abraham in importance.
John 8:58 should read as follows:
John 8:58 Jesus said unto them, Verily, verily, I say unto you, Before Abraham was, I am HE. i.e. the one promised.
‘He’ is added by the translators to make the sense in the following places:
John 9:9 Some said, This is he: others said, He is like him: but he said, I am (ego eimi) he.
John 18:5 They answered him, Jesus of Nazareth. Jesus saith unto them, I am (ego eimi) he. And Judas also, which betrayed him, stood with them.
John 18:6 As soon then as he had said unto them, I am (ego eimi) he, they went backward, and fell to the ground.
John 18:8 Jesus answered, I have told you that I am (ego eimi) he: if therefore ye seek me, let these go their way:
Jesus was foreknown in the same way that all who will be in the kingdom of God are foreknown.
1 Peter 1:20 Who verily was foreordained (proginosko) before the foundation of the world, but was manifest in these last times for you,
Romans 8:29 For whom he did foreknow (proginosko), he also did predestinate to be conformed to the image of his Son, that he might be the firstborn among many brethren.
Jesus certainly did not pre-exist.
Remember also he had to be a physical son of David.
2 Samuel 7:12 And when thy days be fulfilled, and thou shalt sleep with thy fathers, I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom. 13 He shall build an house for my name, and I will stablish the throne of his kingdom for ever.
The idea that Jesus pre-existed with the divine nature and that he put off the divine nature and was born as a baby, is a ludicrous conjecture necessitated by the false doctrine that he is part of a triune God.
No such teaching is found in the Bible.
John 8:58 is just one of the straws that trinitarians clutch at, which exists only because the translators who also believed in a trinity left off the ‘he’ necessary for it to make sense.
I hope you find this helpful.