There are two basic motivations for being radical. There are those who are radical because they want to accomplish something. And there are those who are radical because they believe something has been accomplished. These differences in motivation are sometimes only theoretical, but they are also often crucial. They may mean the difference between frustration and faithfulness.
I am aware that I have led the reader into a dark forest of unexplained words. I have written that first paragraph with precision, and I hope that my meaning will become clear as I define my terms. And as my meaning becomes clear, I trust that the reader will become capable of both intellectual assent and action response.
Let us examine first of all the term radical. According to Webster, a radical is "one that advocates a decided and often extreme change from existing, usual, or traditional views, habits, conditions, or methods." I can subscribe to that description of myself wholeheartedly. The denotation of the word, that is, the strict literal definition, which we find in Webster, is one that should embrace all Christians. The term radical conjures up all kinds of images that we must reject (violence, arrogance, etc.), but we cannot be followers of Jesus Christ and reject radicalism per se.
Light coming into darkness is the radical biblical description of Jesus coming into the world. When light confronts darkness, a change is demanded. The change is so complete that it might actually be termed a reversal. The darkness is transformed so that the end result of the bright light of Jesus coming into a sinful world is "an extreme change from existing ... conditions."