the Holy Spirit as a person is an agent and can by no means be thought of as the means or instrument used by a human agent of baptism. Well, perhaps some people with an inadequate theology of the Holy Spirit have understood things like that, but the whole idea of the Holy Spirit as an instrument or means used by humans sounds frankly blasphemous.

Peter, I too believe that the Spirit is the agent in this passage, but I think you are too hard on those who think differently.

The language of pouring out in Acts 2 and Paul’s metaphor of drinking of the Spirit in this passage show that the Biblical authors weren’t as exact as we are about such things.

Indeed, I think that Luke’s understanding of Spirit-baptism, distinct from Paul’s, has Jesus as the agent ‘baptising’ us by means of (or with) the Spirit. Whether that’s the Spirit empowering him to do so, or the Spirit as that in which we are baptised is beside the point. The metaphor allows for the ‘person’ of the Spirit to be spoken of in impersonal terms (as, in fact, we do with God all the time!).

I should add that I am not arguing that en implies the need for total immersion. I would suggest that sprinkling could be considered baptism en hudati = “in water”, with the water being thought of as the location rather than the means or instrument. But touching a baby’s forehead with a wet finger seems to be rather too far from the original imagery,

I wrote in the original post,

Fee points out that the believers are immersed in the Spirit and drink of the Spirit, two metaphors which emphasize the unity of the believers.

Thank you, Peter, for further explaining Fee’s point.

I note that no one has mentioned the parallel in the second half of the verse, with the Spirit being drunk, which suggests that the image in the whole verse is of the Spirit as a liquid. This strengthens the case for en being metaphorically locative.

In fact in his commentary Gordon Fee more or less assumes this locative interpretation. He notes that verse 9 gives some support for an instrumental en here, but it is a different matter for God to use his Spirit as a means or instrument.

Fee writes “Nowhere else does this dative with “baptize” imply agency (i.e., that the Spirit does the baptizing), but it always refers to the element “in which” one is baptized.” So this agent interpretation has been considered. In a footnote Fee mentions but dismisses the partial parallel at 6:11.

For Fee, “into one body” is “the goal of their common “immersion” in the one Spirit”.

Your examples from elsewhere in Paul and from the Didache confirm a consistent picture: en was used of the physical medium with or in which someone was baptised (living water, sea, cloud) and eis was used of the metaphysical result of the baptism (Christ, Moses, name of Christ. Also there is never a suggestion that the Holy Spirit is the agent of baptism. So in 1 Corinthians 12:13 I prefer “in”, or perhaps “with” as I don’t want to insist on immersion, even metaphorically as here, but not “by” which I see as a theologically tendentious rendering.