I believe we have here one chief reason why so many in this day are inconsistent, trimming, unsatisfactory, and half-hearted in their conduct about the world. Their faith fails. They feel no assurance that they are Christ’s, and so feel a hesitancy about breaking with the world. They shrink from laying aside all the ways of the old man, because they are not quite confident they have put on the new. In short, I have little doubt that one secret cause of “halting between two opinions” is want of assurance. When people can decidedly say, ‘The Lord, He is the God,’ (1 Kings 18.39) their course becomes very clear.

J. C. Ryle, Holiness