The Trinity in the Great Commission — Matthew 28:19

Matt 28:18-20 commissions the church to baptize "in the name (singular) of the Father and of the Son and of the Holy Spirit." One name, three persons: the baptismal formula is implicitly trinitarian.

Augustine — On the Trinity, and Council of Nicaea — Nicene Creed. Gregory of Nazianzus — Theological Orations.

The baptism commanded here is unfolded theologically in Rom 6:3-4, and the abiding presence of 28:20 echoes the Immanuel of Matt 1:23. The triune name is the church's confession and its commission.