It is remarkable that such a crucial aspect of Jewish faith, our eternal hope of survival, is commemorated with a law so narrow in scope. The prohibition of eating the sciatic nerve seems to be a mere technicality in the laws of Kosher, applicable only to the precise nerve that the angel wounded in Yaakov, which is in and of itself only a minor detail in the story of Yaakov's miraculous salvation!
The emphasis on detail in this mitzvah is extremely significant. It highlights that G-d's intimate concern extends even to the most negligible details in the life of a Jew!
Truly, the Baal Shem Tov taught that every single aspect of creation is governed by Divine Providence, and serves a specific role in the Divine plan for the universe. Nevertheless, in the rest of creation, the significance of the role played by each blade of grass is still minor in comparison to that played by the sun or the clouds, or by animals and humans.
Not so in the details which transpire in (and effect) the life of the individual Jew; the health of even a nerve in his hip is as important and cherished by G-d as is the whole of the entire universe and even more so. Each Jew is uniquely chosen by G-d to be a part of His treasured nation, each member of which He loves like His very own biological child. Therefore, even the seemingly trivial details of a Jew's life are of infinite and essential importance to Him and are His most pressing issue and concern.