Why prepare the beard for shaving? Why not just start slinging lather and flashing steel? There really are two reasons: the first is to avoid nicks and cuts; the second, and equally as important, is the desire for a perfectly shaved visage.
While there are many ways to approach shave preparation, they all have the same goal and that is to soften the beard by hydrating it. Some gentlemen achieve this goal by simply showering before shaving, finding the lengthy exposure to hot water while cleansing the body also adequately hydrates the beard. Others do not have the latitude or desire to prep in this way. Many of these gentlemen find merely washing the face and neck with a gentle facial scrub or facial soap provides a face and beard ready for the warm, fragrant lather to follow. Others gents take this approach somewhat further and follow face-washing with a hot (as hot as can be safely accommodated) washcloth wrapped around the face and neck for a few minutes. There are some gents who apply a coat of lather after the wash, then wrap their face and neck with a hot wash cloth or hot towel for several minutes providing for additional beard softening. Then there are those gents who in addition to using one of these methods to soften their beards, also apply one of the many pre-shave products presently available on the market for the extra lubrication and beard softening provided by such products.
Whether you choose to follow one of these regimes or arrive at your own, your success will be measured in how well your beard has been hydrated and thereby softened before it meets your razor.