Baptism is always Trinitarian. The teaching & theology of the NT Letters proves this (1 Pet. 1:2 / Tit. 3:4-6). Both the economic but most important an ontological reality in God’s Triune unity and character. There can be no economy of God without also His own ontology: being & substance!

On Acts 2:38, Calvin wrote: “I maintain that Peter is not speaking in this passage of the form of baptism but simply declaring that the whole efficacy of baptism is contained in Christ; although Christ cannot be grasped by faith without the Father by whom he was given and the Spirit by whom he renews and sancifies us.

Calvin knew that the Greek prepositions in the Book of Acts as to the doctrine of baptism supports the reality of Christ being the one in authority and sovereign in the command to baptise, rather than the formula, etc. And we need to also note that the Gentiles were not regenerated by the water in baptism, as they were filled (made regenerate) with and by the Holy Spirit even before the act and action of baptism (Acts 10:44..etc.) “And he (Peter) ordered them to be baptised in (by the authority of) the name of Jesus Christ.” (verse 48)

Fr. Robert