By whom we have received grace and apostleship, for obedience to the faith among all nations, for his name:...But now is made manifest, and by the scriptures of the prophets, according to the commandment of the everlasting God, made known to all nations for the obedience of faith...." -- The Apostle Paul, Romans 1:5, 16:26
In an 1822 sermon delivered before the American Board of Commissioners for Foreign Missions in New Haven, Connecticut, Alexander Proudfit, Associate Reformed minister, explained what is the key to the success of worldwide missionary endeavors. The sermon was titled The Universal Extension of Messiah's Kingdom, and throughout, he emphasizes the promises of God for the success of this endeavor through the means appointed. And the key means that God has appointed for the Great Commission is, simply put, faithful preaching.
"But there is another and still more powerful means, by which the Gospel is to be diffused among the nations; -- the preaching of the word of reconciliation. The Scriptures, translated and distributed, will probably remain a dead letter, unless accompanied with the ministrations of the living teacher. Far be it from me to detract from the importance of Bible Societies, or to utter a remark, which might tend to relax the exertions of those who are engaged in the honorable work of diffusing the Scriptures. Let associations of this character be formed; let copies of the sacred volume be multiplied; let them be dispersed through every country; let them be conveyed into every house, and placed on the shelf of every habitation of mankind. Let all this be done with a zeal answerable to the unutterable importance of the work; yet I venture to assert, that it is by the preaching of men, enlightened, ardent, self-denied, disinterested men; by the preaching of such in a pre-eminent degree, that the nations are ultimately to be subdued to the obedience of faith" (p. 15).