Profession a necessary (if hardly sufficient) condition

"when the Scripture speaks of Christian practice, as the best evidence to others, of sincerity and truth of grace, a profession of Christianity is not excluded, but supposed."

     Jonathan Edwards, The religious affections, pt. 3, sec. 12 ((WEJ 2, ed. John E. Smith, 412; Edinburgh: The Banner of Truth Trust, 1986 [1961]), 332), italics mine.  "Though in these rules, the Christian practice of professors be spoken of as the greatest and most distinguishing sign of their sincerity in their profession, much more evidential than their profession itself; yet a profession of Christianity is plainly presupposed:  it is not the main thing in the evidence, nor anything distinguishing in it; yet 'tis a thing requisite and necessary in it."