"I consider the most dangerous champion of the Sadducee school is not the man who tells you openly that he wants you to lay aside any part of the truth, and to become a free-thinker and a skeptic. It is the man who begins with quietly insinuating doubts as to the position that we ought to take up about religion, doubts whether we ought to be so positive in saying "this is truth, and that falsehood," doubts whether we ought to think men wrong who differ from us on religious opinions, since they may after all be as much right as we are.
It is the man who tells us we ought not to condemn anybody's views, lest we err on the side of the lack of love. It is the man who always begins talking in a vague way about God being a God of love, and hints that we ought to believe perhaps that all men, whatever doctrine they profess, will be saved. It is the man who is ever reminding us that we ought to take care how we think lightly of men of powerful minds, and great intellects (though they are deists and skeptics), who do not think as we do, and that, after all, "great minds are all more or less, taught of God!"
It is the man who is ever harping on the difficulties of inspiration, and raising questions whether all men may not be found saved in the end, and whether all may not be right in the sight of God. It is the man who crowns this kind of talk by a few calm sneers against what he is pleased to call "old-fashioned views," and "narrow-minded theology," and "bigotry," and the "lack of liberality and love," in the present day. But when men begin to speak to us in this kind of way, then is the time to stand upon our guard. Then is the time to remember the words of our Lord Jesus Christ, and "Be careful and be on your guard against the yeast."
Once more, why do I say this? I say it because there is no security against Sadduceeism, any more than against Phariseeism, unless we resist its principles in the bud. Beginning with a little vague talk about "love," you may end in the doctrine of universal salvation, fill heaven with a mixed multitude of wicked as well as good, and deny the existence of hell. Beginning with a few high-sounding phrases about intellect and the inner light in man, you may end with denying the work of the Holy Spirit, and maintaining that Homer and Shakespeare were as truly inspired as Paul, and thus practically casting aside the Bible. Beginning with some dreamy, misty idea about "all religions containing more or less truth," you may end with utterly denying the necessity of missions, and maintaining that the best plan is to leave everybody alone.
Beginning with dislike to "Evangelical religion," as old-fashioned, narrow, and exclusive, you may end by rejecting every leading doctrine of Christianity--the atonement, the need of grace, and the divinity of Christ." —J. C. Ryle (1816-1900)
Excerpt taken from a sermon titled "Warning to the Church: Pharisees and Sadducees" by J. C. Ryle (1816-1900)