Robert Traill (Stedfast Adherence to the Profession of our Faith), Works 3:18:
Christian profession must be visible. Profession is mainly for others, as faith in the reality of it is mainly for ourselves: the apostle therefore, when he is speaking of the great profession of the faith of the patriarchs, saith, Heb. 11:13, 14, They confessed that they were strangers and pilgrims on the earth. And they that say such things, declare plainly that they seek a country, etc. All who had known Abraham, and Isaac, and Jacob, who saw their way of living, who beheld their way of not mixing with the rest of the nations, who beheld their faith and hope; these might have seen plainly, these were men for another world than this. There can be no profession unless it be visible. This is so general and well known a thing, that a visible credible profession of Christianity is that only that deserves this name.
Source: http://www.puritanboard.com/threads/men-for-another-world-than-this.91867/, Comment 1