Relativism says this: “truth is what you perceive it to be, and what is true for you may be false for somebody else.” In our present society, you’re perfectly free to believe whatever you like, but the one thing you may not do is to deny its antithesis. You can say, “I believe that this is true.” But you cannot say with impunity that that which opposes it is false. We have a whole generation of Christians who have been brainwashed by the spirit of relativism so they’re completely hesitant to say, “I deny that error over there.” We don’t have heresy trials anymore because, in relativism, there is no such thing as heresy.
R.C. Sproul