A.T. Robertson Commentary John 3:31

"He that cometh from above is above all: he that is of the earth is of the earth, and of the earth he speaketh: he that cometh from heaven is above all." — John 3:31 (ASV)

Is above all (επανω παντων). Ablative case with the compound preposition επανω. See the same idea in Ro 9:5. Here we have the comments of Evangelist (John) concerning the last words of John in verse 30 which place Jesus above himself. He is above all men, not alone above the Baptist. Bernard follows those who treat verses 31-36 as dislocated and put them after verse 21 (the interview with Nicodemus), but they suit better here.

Of the earth (εκ της γης). John is fond of this use of εκ for origin and source of character as in 1:46; 1 John 4:5. Jesus is the one that comes out of heaven (ο εκ του ουρανου ερχομενος) as he has shown in 1:1-18. Hence he is "above all."