A.T. Robertson Commentary John 1:32

"And John bare witness, saying, I have beheld the Spirit descending as a dove out of heaven; and it abode upon him." — John 1:32 (ASV)

Bare witness (εμαρτυρησεν). First aorist active indicative of μαρτυρεω. Another specimen of John's witness to the Messiah (1:7,15,19,29,35,36).

I have beheld (τεθεαμα). Perfect middle indicative of θεαομα, the realization of the promise of the sign (verse 33) by which he should recognize the Messiah. As a matter of fact, we know that he so recognized Jesus as Messiah when he came for baptism before the Holy Spirit came (Matthew 3:14ff.). But this sight of the Spirit descending as a dove upon Jesus at his baptism (Matthew 3:16; Luke 3:22) became permanent proof to him. John's allusion assumes the Synoptic record. The Semites regarded the dove as a symbol of the Spirit.