"No one wants to be labeled a legalist. It is resoundingly negative and is used in polemics solely of others, never of oneself. The accused, of course, reject the label. To give just one example from many, Seventh-day Adventists are often said to be extreme legalists, because of their views of the Sabbath, dietary regulations, advocacy of tithing, and prohibition of drinking and smoking. Denying that they are legalistic, they insist that out of thankfulness to Christ, by whose grace they have been saved through faith, they obey his will as the Scriptures reveal it.3 Further instances of this strongly polemical use in academic biblical studies, practical theology, and popular Christian literature could easily be multiplied.4 In spite of widespread use, the term “legalism” is employed in a variety of ways, usually without a great deal of attention to definition. Too often, it is simply assumed that the reader will understand what is meant by the term—and whatever that is, it is, without doubt, bad. Some may be surprised to learn that, in fact, little careful work has been done on defining this term in biblical and theological studies, the arenas of its greatest use."
Yinger, Kent, "Defining Legalism" (2008). Faculty Publications - Portland Seminary. 82.