Your sermon should make it clear that there will always be false prophets who seek to draw us away from Christ and what he has taught. As a result, we must be on our guard and we must discern between the true and the false. You will explain what the two marks/tests are that can help us in our discernment.
15 Gardez-vous des faux prophètes. Ils viennent à vous en vêtements de brebis, mais au-dedans ce sont des loups ravisseurs.