In Parasha Netzavim, Devarim 30:16, we learn the commandment to love Hashem, to walk in His ways, and to keep "His commandments [mitzvosav] and His statutes [v'chukosav] and His ordinances [u'mishpatav]." I thought this verse might be distinguishing between the written Torah, oral Torah, and rabbinic law, or perhaps between Torah, rabbinic law, and customs. But I can't find a source that explains this. To what is the verse referring?
חוקים (Hukim) are generally considered laws that the logic behind them may be obscured, and not easily understood. An example of this is the law of פרה אדומה
משפטים (mishpatim) are generally laws that their logic is more apparent for the wellbeing of civilization such as do not murder. For more in depth discussion, see for example: http://www.kipa.co.il/jew/pash/52/42814.html