After crossing the Yam Suf via miraculous intervention, Bnai Yisrael find themselves in Marah without drinking water. They complain to Moshe who in turn beseeches Hashem; Hashem instructs Moshe to throw a piece of wood into the bitter waters of Marah and the waters become sweetened (שמות ט"ו:כ"ב-כ"ה). Following this, the Torah says, "שם ”ם לו חק ומשפט," "there, He established a statute and a law" (שם פסוק כ"ה). Rashi, citing the Gemara in Sanhedrin (דף נ"ו:), claims that this means that certain Parshiyos of the Torah were taught just then to Bnai Yisrael, so that they would have something with which to involve themselves. Among these laws were some details about Shabbos, Kibbud Av VoEim (which is what the text in Rashi should state, in place of Parah Adumah, as pointed out by the Torah Temimah there in אות ל"ו, among others) and about establishing a court system. The question is, if Bnai Yisrael were only six weeks away from their arrival at Har Sinai, why did Hashem find it necessary to share with them any Mitzvos at this time? What value was there in addressing a handful of Mitzvos prior to having the people hear the Aseres HaDibros at Har Sinai?
Before giving Bnai Yisrael the Torah, Hashem sent Moshe as His emissary to see if Bnai Yisrael were prepared to accept the responsibility of being a ממלכת כהנים וגוי קדוש, a kingdom of priests and a holy nation, as they are later described by the Torah (שם י"ט:ו'). Bnai Yisrael responded to Moshe's inquiries by stating "כל אשר דבר ה' נעשה," "we will do all that Hashem tells us" (שם פסוק ח'). Most people generally assume that Bnai Yisrael stated that declaration without having any prior knowledge as to what this might entail. One may, however, argue that this is not the case. Bnai Yisrael most likely could not have responded in the affirmative to the charge of being a גוי קדוש, a holy nation, without having any understanding as to what comprises a גוי קדוש. It is for this reason that Hashem first shares with Bnai Yisrael several Mitzvos, each of which is symbolic of a general category of Mitzvos.
The establishment of the judicial system, known as דינים, for example, is symbolic of all the מצוות בין אדם לחבירו, the Mitzvos relating to man and his fellow man, because the court is the agency that enforces compliance with all such Mitzvos. Shabbos, on the other hand, is the paradigm of a מצוה שבין אדם למקום, a Mitzvah focusing on the relationship between man and Hashem. Bnai Yisrael must be cognizant of the fact that in order to be a גוי קדוש, they must be committed to both domains, the Mitzvos which effect their relationships with each other, and those that impact their relationship with Hashem.
Lest one think, however, that these represent two separate and unrelated domains, Hashem also shares with them the Mitzvah of Kibbud Av VoEim which touches upon both areas. One is to honor his or her parents both in deference to Hashem's command and because one recognizes all of the efforts and energies which the parent has expended on his or her behalf. Having practiced and observed these Mitzvos for six weeks beginning at Marah, Bnai Yisrael were indeed tested, as the Posuk says, "ושם נסהו," "there they were tested" (שמות ט"ו:כ"ה). They were then truly prepared for the moment when they could sincerely say those powerful words, "כל אשר דבר ה' נעשה", "we will do all that Hashem tells us" (שמות י"ט;ח').