First, evangelism as sacrament. We know it's not about the signs and the wonders (after all, even the gods of the Egyptians were highly adept at doing signs and wonders and even some of us ordinary, average human types are pretty good at fabricating illusions) but our scriptures - and Jesus! - are clear it's ultimately about the sacrament, about the constant, unmediated, unqualified presence of God and the evidence thereof, absolutely everywhere, absolutely all the time. And since we're Christians, "little Christs" we're called to be part of that sacramental evidence of God-among-us and God-with-us.
"All Nations," since Jesus commanded us to evangelize the world: we have the complete "7" in the 7 Pauline churches, the 7 churches in Revelation: the whole, entire, known inhabited world! So we need to be "ecumenical" in the broadest and best sense of the word! Every single church of whatever denomination literally is supposed to be a "church of God in Christ" and each of us essential members of that church.
Of course, those baptizers-among-the crocodiles in The Poisonwood Bible probably didn't realize baptism really isn't effective fire insurance; it's a *sign* and symbol of God's salvific action in Christ.
"...in the context of the Great Commission," baptizing *them* in he name of the Father, Son and Holy Ghost...though I'll be thinking about it, right now I'll say it means incorporating them into the history, the covenants and the reality of earthbound living that's also life in the Spirit right here and now, Pentecostal living. Baptism calls us to creativity, to mercy, love and justice and to freedom and re-creation, a three-fold expression of the sacramental (communion-like, as in Holy Communion) our living baptized into Good Friday and Easter Dawn! I've mentioned somewhere that Walter Brueggemann says Holy Communion is "pre-Eucharist," sometimes with a greater sense of really and truly actual presence.