This question has bothered me for years. The Torah goes into tremendous detail about the construction of the mishkan not once but twice, once the command and once the actual building. The obvious question is what is this coming to tell us? Why does the Torah give so much detail here when most mitzvos get almost no detail. Just a few examples
1. tefillin has 1 vague pasuk from which we can understand little
2. The torah says don't do melacha on shabbos and never defines melacha (in Torah Shebicsav)
3. The torah says many times to shcecht but never explains what shechita is.
In short, most mitzvos have very little in teh Torah Shebicsav, most of teh mitzva is expounded in Torah Shebaal Peh, the contruction of teh mishkan on the other hand has tremendous detail in the Chumash.
What makes this even more troubling is that the construction of the mishkan was a horaas shaah. The mitzvah ledoros is to build the Beis Hamikdash, if so why does the Torah go into all this detail about building the mishkan?
I have not seen a good answer for this. Any answers would be appreciated.