The law of the red heifer is a great puzzle and there are countless theories to explain it. In Jewish tradition, it is the paradigm of the Divine “statute” which must be obeyed regardless of whether we are sure of its rationale.
The question is whether our intellect is comfortable with this approach. If we do not really understand a law, can we (conveniently?) shut reason off and obey blindly?
Surely Jewish law would not accept the idea of blind obedience and prefers the concept of loyalty.
When we say we believe in God we mean that we trust in Him and we trust Him. We are certain that in the Divine wisdom everything makes sense. Out of loyalty we say, Na’aseh v’nishma – “we will do and hearken”.
We have enough experience of His law to know that it is full of sound judgment and if there are aspects which we do not (yet) understand we know we can rely on Him.