Q. Why do we not mix milk and meat?
One of the important aspects of observing kosher is keeping milk and meat properly separated. This prohibition is derived from the verse, "Do not cook a kid in its mother's milk." This verse appears in the Torah three times, twice in Exodus (23:19 and 34:26) and once in Deuteronomy (14:21). According to Jewish tradition,
According to Jewish tradition (Talmud Chullin 113b), the Hebrew word g'di (kid goat) is understood to mean any young domestic animal—not only a kid goat. The repetition of the verse teaches us that it is not only forbidden to cook meat and milk together, but it's also forbidden to then eat or derive benefit from the mixture. In fact, the Torah forbids the cooking, eating and benefit of the meat of any kosher domesticated animal, in any kosher milk. The Torah simply gives an example of a "kid in its mother's milk" because that was common practice in ancient times.
Some Jewish authorities give reasons for this prohibition. One reason given is, that it is cruel to cook a baby in the very milk that was intended to nourish it. The Torah forbids the cooking and consumption of any milk with any meat to prevent one from cooking a kid in its mother's milk.
According to Kabbalah, meat represents gevurah (the Divine attribute of Judgment) and milk represents chesed (the Divine attribute of Kindness). These two opposing characteristics are not to be mixed with each other.
None of these reasons are fully satisfactory and it is clear that this mitzvah falls into the category of Mitzvahs that have no satisfactory reason - Chukim. The reasons of many of the commandments in the Torah are beyond our comprehension. This allows for our acceptance of a Higher reason and the realization that our comprehension is limited.