I've been searching the origins on the phrase (not the teaching or concept, but the actual phrase)
Baptism as an act of obedience.
Does any Baptist know who coined the term? It's been very hard to track down when that phrase came into use or who first expressed it in that way.
I haven't found it in the reformers writings, nor in the Westminster or London Confessions, Jonathan Edwards, Charles Spurgeon, Charles Finney, or Billy Sunday.