“as he stepped away from the water.” The heavens did not open and the holy spirit descend while Jesus was standing in the Jordan River, but as he came “away” (apo) from the river and stepped up onto the bank. This fact becomes especially clear when Matthew is read in harmony with Mark. Here in Matthew 3:16, “away from” is from the Greek preposition apo (away from). The only way to be “away from” the water is to be out of it. Leon Morris (The Gospel According to Matthew) writes:
Matthew does not describe the baptism, but takes up his narrative from the time when it was completed...He uses the preposition apo (which he uses 113 times) whereas Mark uses ek (Mark 1:10). But Matthew has no dislike for ek, for he uses it 82 times, so he is not simply avoiding Mark’s preposition. He may, of course, use apo to indicate “more clearly Jesus’ complete departure from the waters of the Jordan” than does Mark’s ek....
Robert Gundry writes: “[Matthew] makes Jesus go up from the water immediately after the baptism, i.e., clamber up on the riverbank...Matthew’s apo does not negate the thought of emergence contained in Mark’s ek, but it indicates more clearly Jesus’ complete departure from the waters of the Jordan” (Matthew: A Commentary).
Other commentators make note of the fact that by leaving John and stepping out of the Jordan River, Jesus is shown to be starting his own new ministry, not connected with John the Baptist. Davies and Allison (The International Critical Commentary) make that point: “Jesus’ emerging from the water and climbing the bank...connects the heavenly vision and voice not with an action of John but with an action of Jesus.” They further state that it brings to mind at least two strong images that are imbedded in the Jewish mind: the creation of order from watery chaos (Gen. 1:2), and Israel’s new beginning as it came up and out of the Red Sea. Jesus’ coming up out of the Jordan marked the start of something new. [For more on Jesus’ baptism, see commentary on Mark 1:10].
“Look!” The Greek word is idou (#2400 ἰδού), and it is used to get our attention. See commentary on Matthew 1:20 (“Look!”).
“he saw the spirit of God descending.” In Matthew, Mark, and Luke, the “he saw” can refer to Jesus or John, the pronouns are unclear. But in any case, this was an event visible to anyone there and John did actually see it (John 1:32). The fact that the spirit came down upon Jesus was important because it openly demonstrated to the world that Jesus had been “anointed” with holy spirit, something that normally cannot be seen (cp. Acts 10:38).
In this video John Schoenheit looks at the account of Jesus being baptized and what order events actually happened.