"...and he saw the Spirit of God descending like a dove and coming to rest on him...." (Matthew 4:16)
"...immediately he saw the heavens opening and the Spirit descending on him like a dove." (Mark 1:10)
"...and the Holy Spirit descended on him in bodily form, like a dove...." (Luke 4:22)
"'I saw the Spirit descend from heaven like a dove, and it remained on him.'" (John 1:32)
Since I follow a lectionary from Advent through Pentecost, I annually contemplate the baptism of our Lord. The narratives suggest, and many people often assumed, that when the Holy Spirit descended on Jesus, his body was that of a dove. However, as several commentators observe, the texts uniformly state that the Spirit's descent was like that of a dove, not that the Spirit took on the form of a dove. The closest an Evangelist gets to describing the Spirit's appearance is in Luke 4:22; even there, the most one could say is that the Spirit looked like a dove. "Like" becomes a sort of veil, obscuring the Spirit's appearance.
Why was the Spirit, when he spoke through the Evangelists, so scrupulous about avoiding a plain description of his appearance when he descended and alighted on Jesus? The best explanation I've been able to come up with is the Second Commandment; that is, a clear description of God the Spirit's appearance is denied us (just as we never get a clear description of God the Son's Incarnate appearance) in order to keep us from constructing images to aid us in our prayers, meditations, and worship.
