A.T. Robertson Commentary John 3:8

"The wind bloweth where it will, and thou hearest the voice thereof, but knowest not whence it cometh, and whither it goeth: so is every one that is born of the Spirit." — John 3:8 (ASV)

The wind (το πνευμα). In Greek πνευμα means either wind or spirit as spiritus does in Latin (so also in Hebrew and Syriac). Wycliff follows the Latin and keeps spirit here and Marcus Dods argues for it. The word πνευμα occurs 370 times in the N.T. and never means wind elsewhere except in a quotation from the O.T. (Hebrews 1:7 from Ps 104:4), though common in the LXX. On the other hand πνεω (bloweth, πνε) occurs five times elsewhere in the N.T. and always of the wind . So φωνη can be either sound (as of wind) or voice (as of the Spirit). In simple truth either sense of πνευμα can be taken here as one wills. Tholuck thinks that the night-wind swept through the narrow street as Jesus spoke. In either case the etymology of πνευμα is "wind" from πνεω, to blow. The Spirit is the use of πνευμα as metaphor. Certainly the conclusion "of the Spirit" is a direct reference to the Holy Spirit who works his own way beyond our comprehension even as men even yet do not know the law of the wind.