In every generation God has sent His servants to rebuke sin, both in the world and in the church. But the people desire smooth things spoken to them, and the pure, unvarnished truth is not acceptable. Many reformers, in entering upon their work, determined to exercise great prudence in attacking the sins of the church and the nation. They hoped, by the example of a pure Christian life, to lead the people back to the doctrines of the Bible. But the Spirit of God came upon them as it came upon Elijah, moving him to rebuke the sins of a wicked king and an apostate people; they could not refrain from preaching the plain utterances of the Bible—doctrines which they had been reluctant to present. They were impelled to zealously declare the truth and the danger which threatened souls. The words which the Lord gave them they uttered, fearless of consequences, and the people were compelled to hear the warning.
Thus the message of the third angel will be proclaimed. As the time comes for it to be given with greatest power, the Lord will work through humble instruments, leading the minds of those who consecrate themselves to His service. The laborers will be qualified rather by the unction of His Spirit than by the training of literary institutions. Men of faith and prayer will be constrained to go forth with holy zeal, declaring the words which God gives them.
-The Great Controversy, page 606