He that cometh from above is above all: he that is of the earth is earthly, and speaketh of the earth: he that cometh from heaven is above all. And what he hath seen and heard, that he testifieth; and no man receiveth his testimony. - John 3:31-32
Here we have two distinct "he" in view: "he" from above (heaven) and "he from below (earth), see John 8:23
The "he from the earth is represented by 3rd person singular pronoun: Of the earth "he is" and of the earth "he speaks".
The "he from above is also represented by 3rd person singular pronoun: From heaven "he is" and what "he testifies" here (and which no man receives) is what "he has seen" and "he has heard" there (heaven above).
There are those who disbelieve that the Son of God had a personal pre-existence prior to being born of a virgin and given the name of Jesus. The claim, as I understand it, is that prior to the birth of Jesus all reference to "him" is a reference to the Logos as the non-personal "plan of God". See this related question as an example.
For those who deny the pre-incarnate personal existence of the Son of God:
In the very direct comparison of John 3:31-32, How is it that 3rd person singular can refer to person-hood in "he who is from the earth" but not person-hood in "he who is from above"?
Secondarily, How can "he from above" have seen and heard that which "he" later testifies if "he" had no person-hood prior to earthly existence? Can a plan see, hear, and remember in order to later testify?