I should preface this with the statement that I personally think that the Karaitic interpretation of the pasuk to mean one must sit in one's house all Shabbos in the dark and cold to be ridiculous and not the true peshat in the pasuk. The reason for that I will have to save for another post, perhaps next week.
But looking at the Karaitic position, in their own words, is interesting. It lets us see this famous debate from their perspective, and how they reacted to the polemics and arguments from the Prushim. And so of course I knew I wanted to see what the Karaite scholar, Aharon ben Yosef, had to say about these pesukim. I present his commentary and the supercommentary on it, in my own rough summary, with occasional interjection.
In the beginning of Vayahkel:
The Ktav Ashru are the words of Aharon ben Yosef, and the Rashi script (below) is the supercommentary.
"Eleh HaDevarim" includes the construction of the Mishkan as well not doing work on Shabbat. And he shows with evidence from pesukim that prohibitions can fall under the lashon of tzivuy.
It mentioned refraining from work on Shabbos in Ki Sisa. Why did it not mention burning a fire - a short style.
He deals with why it needs to mention it (fire) here -- so that you should not say that since the work on the Mishkan did not cancel Shabbos, we might say there should be no fire on the altar, for burning is within not doing any work, therefore it lays out that in your homes (במושבותיכם) it is forbidden but not in the Beis Hamikdash.
The impetus for explaining the reason for specifying lo tevaaru is likely the Rabbinic derasha that it was for the sake of the lav, or else lechalek, as he continues. But I am not so impressed with this explanation. Surely many other pesukim discuss the burning of the korbanot for Shabbat, so who would possibly think that the fire could not be burning on the altar?
He dismisses being liable on each violation individually as obvious. I am not so sure it is obvious, but anyway it is on the level of derash.
He considers that it was because ochel nefesh is permitted on Yom Tov, so it must specify that it is not on Shabbat -- the suggestion of Ibn Ezra -- because we can derive it anyway from the word Ach "Ach Asher Ye'achel l'Chol Nefesh." Is he now darshening, or arguing according to the Rabbinic approach? Karaites do have their own derash. But IIRC, on a peshat level, Ach does not mean "only" as a limiting term in Biblical Hebrew, and modern scholars will tell this to you -- that it is an intensification, such as "indeed" or "surely" on a peshat level in Biblical Hebrew.
And the word "esh" shows that it means a language of fire and lighting. This in contrast to the one who explains it means "cast out." He refers here to a nice explanation of Rav Saadiah Gaon, as part of this Rabbinic-Karaitic polemic. Rav Saadiah Gaon said it meant "cast out," as is "uviarta hara mikirbecha." Therefore, the pasuk is saying that you shoud not chase out the fire from your house, and thus we have a source that the ner shel Shabbos is a mitzvah. This is remarkably clever and probably riled up the Karaites, with an explanation exactly against their idea of sitting in the dark from the same pasuk. It is obviously not peshat but it does make something nice to say over at your Shabbos table.
He also argues against those who say "the day of Shabbat" would imply only the day and not the night, like "bayom haShemini." This would be Rav Saadia, who was arguing this, that one might say this if you did not rely on the tradition. (And apparently a similar argument put forth by Ibn Ezra.) Aharon ben Yosef gives a reason to make a distinction -- because the word Shabbat carries this implication, of from evening to evening. This seems to me like a "teretz." Maybe what was meant was the day portion of Shabbat, the day of rest? But my intent here in this post is not to wage war against the Karaites, so I will leave it here. One may argue it the other way, naturally.
Thus, we have a nice overview of a Karaitic approach to these pesukim. Perhaps in a later post, why I consider this approach most unlikely, and my own novel suggestion on the role of lo tevaaru.