I like to read the works of really old theologians, and the other day I was reading a selection from a Scottish author named George MacDonald (1824-1905).
MacDonald definitely had a way with words, and these words have stuck with me ever since I read them:
Instead of asking yourself whether you believe or not, ask yourself whether you have this day done one thing because He said, Do it, or once abstained because He said, Do not do it. It is simply absurd to say you believe, or even want to believe, in Him, if you do not do anything He tells you.
This is the heart of discipleship that must be regained in modern Christianity – starting with me and starting with you.