3:15 Luke here uses the word, "prosdoka-oo" for "wait" or "expect." Interestingly, Luke uses this word a whole bunch (6x in Luke; 4x in Acts), far more often than anyone else. In this case though, the people are not waiting for Jesus, per se, but rather the Messiah, and wondering whether John would be it. Perhaps a reminder and a challenge -- what are we waiting for?
3:15 The people wondered "in their hearts." (kardias) In Luke's Gospel, the hearts is the place where thought occurs, much like Hebrew!
3:15 The word here for "is" is in the optative mood, a rare usage indeed. Gotta give it to Luke -- using Hebrew thought with advanced Greek!
3:16 The word for gather here is "synago" An interesting connection to Baptism indeed, that Jesus will gather, literally, make the the church! Okjay, its abstract, but I think helpful.
3:18 Luke uses the word "euangeliz-oo" here to describe the work of John. Most Lutheran preachers might want a bit more Jesus/Gospel to use this word!
3:21 Once again the Gospel of Luke, we find Jesus praying. The word "praying" is a present participle in this case, which means it is a concurrent action. The question of course, if which verb is it concurrent with: the Baptism or the opening of the heavens? The Greek here presents a grammatical ambiguity; perhaps it alludes to a spiritual mystery. Its intersection points toward another insight: Prayer is what unlocks the power of our Baptism. God has claimed us and established a relationship with us. Prayer is how we live into this relationship -- how the heavens are opened to us.
3:21 The word baptize is used four times in a few verses here. I think Luke wants to draw our attention to the actual action. Perhaps to tie it back to prayer, because of the act of Baptism, we always here the answer to our own prayers: That we are a beloved child of God and brother of Jesus Christ, claimed in the waters.
3:22 At Christmas we celebrate the incarnation of the flesh; in Baptism we celebrate the incarnation of the Spirit! The Holy Spirit fleshed itself -- it came "soma" (body) style!