This parsha starts with a discussion about keeping shabbat and not burning fire on shabbat. Why is this discussion in the middle of the description of the mishkan (tabernacle)? Rashi says this teaches not to do work of mishkan on shabbat. And therefore we learn that all 39 forms of work which were done in the mishkan are forbidden on the shabbat.

But in Parshat Kitisa, the pervious parsha, in chapter 31 verse 13 it is written "Ach et shabbtotai tishmoru" ("But you must keep my Sabbaths") - Rashi says teaches that the work on mishkan must be stopped on shabbat, and therefore teaches 39 malachot.

Why two sources for the same thing? Talmud in Shabbat 71 actually learns from this parsha, not kitisa. Why? Ki tisa is God telling Moshe. Vayakel is Moshe telling the people. Should not we learn from the place where the Law is originally taught by God? But no, The Torah is man's Torah, so we learn the oral law from the place where Moshe our teacher tells us. This puts man squarely in the center of the law.

Interesting things in prev parsha

End of ki tisa 34:34  mask of moshe . 

2. ohel moed versus mishkan, moshe's tent is also called ohel moed, but so is inner part of mishkan.

© Nachum Danzig