“Our task this evening is to go in pursuit of a mystery and its implications for how we believe and how we live our lives.” It is with these words that Dr. John D. Rempel began his lecture, “An Impossible Task: Trinitarian Theology for a Radical Church?” in front of a packed audience at the Toronto Mennonite Theological Centre on the evening of Thursday, March 14th. In his wide-ranging lecture, Rempel explored Trinitarian thinking from the 4th to the 20th century, noting the consistent challenges brought against it from “un-trinitarian expressions of belief.”