“It is, however, vital to understand that, although ‘Christianity begins with a triumphant indicative’, it does not end with one. Certainly, the indicative mood in Christianity enjoys a preponderance; it does not, however enjoy an exclusiveness. Christianity is not altogether in the indicative mood. Indeed, although there is a primacy and a priority about the indicative mood in preaching, there is actually an incompleteness and an insufficiency about the indicative mood considered in isolation.
“The indicative needs to be complemented and supplemented by the imperative; proclamation needs to be complemented and supplemented by appeal; explication [explication] needs to be complemented and supplemented by application [application]. Dr. Sinclair B. Ferguson correctly emphasizes that in preaching, as in the Scriptures themselves, ‘indicatives lead to imperatives.’”
From The Imperative of Preaching: A Theology of Sacred Rhetoric, by John Carrick (p. 83, italics his).