This week's Torah portion begins with, and is named after, the key word chukat. Chukat means "the law of" and specifically refers to the ritual law of the red heifer. What distinguishes a chok from other kinds of laws is its mystery.
Most Torah commandments have a basis in reason and logic. Chukim cannot be justified by rational arguments. There is no plausible explanation for why the ashes of an unblemished red cow are particularly powerful against ritual impurity. Nor can intellectual arguments justify why those ashes should have the paradoxical effect of purifying an impure Israelite, but rendering a priest who handles them impure. The chok of the red heifer, like the chok not to wear a blend of wool and flax, doesn't claim to be reasonable. It claims to be holy and to foster holiness.
Often people will tell me that what they love about Judaism is the freedom to question, to challenge and to demand answers.