In Bava Metzia 59a, Rav Yehuda recommends ensuring you have a ready supply of grain in your house, for discord is found only when grain is lacking. His prooftext is Tehillim 147:14, “He makes your borders (גְּבוּלֵךְ) peace; He satiates you with cream of wheat (חֵלֶב חִטִּים).” I’d add: “your borders” is equivalent to “your house”, as we see from the chametz / se’or prohibition, though on Pesach, we eliminate much of the house’s grain, if it’s leavened. Also, I wonder if there’s a Biblical parallelism or resonance in the verse. Biblical גְּבוּל regularly means border, and only means mixing / kneading post-Biblically (e.g. גַּבֵּיל לְתוֹרָא גַּבֵּיל לְתוֹרֵי in Bava Metzia 69a, mixing fodder for an ox, mix fodder for oxen, or Pesachim 34a, אַבָּא שָׁאוּל גַּבָּל שֶׁל בֵּית רַבִּי הָיָה, Abba Shaul was the dough kneader of Rabbi Yehuda HaNasi’s house). Still, the chains of gold of Shemot 28:14 are מִגְבָּלֹת, twisted / braided, so the root might carry this kneading meaning in Biblical Hebrew as well. Compare also גבב, to give a rounded shape, connecting kneading and border.
גבול technically means "territory" in Tanach, with border as a secondary, though intimately related, meaning. But I like your take, too.
Do you have a source for your take on תשביתו? That might answer a difficulty with the passuk and still fit with the Gemara, in a way. A literal translation of the passuk might be "Seven days unleavened bread shall ye eat, but on the first day ye shall put sourdough to rest; for any eater of leavened bread, [and] cut off that person will be from Yisrael, from the first day until the seventh day." Most switch the order of the last two phrases so it reads "any eater of leavened bread from the first day until the seventh day, that person will be cut off" but maybe "for any...Yisrael" is parenthetic, explaining why sourdough is forbidden, and the main verse is "Seven days unleavened bread shall ye eat, but on the first day ye shall put sourdough to rest...from the first day until the seventh day." Now you have two "first days" and you can have one be the day before, and say אך divides and translate "Seven days unleavened bread shall ye eat, and for part of the first day ye shall put sourdough to rest...from the first day until the seventh day." Don't know if that fits the Gemara, though.
No source for tashbitu, other than a grammatical analysis (of causitive) and general meaning of $-B-T, like in tishbot, בחריש ובקציר תשבות. About gevul and border vs. territory, yes, someone was telling me that the other day.
Maybe it can be aligned with the gemara, but I'd suspect it would be a big kvetch. The way I envision it is that the rest begins on the first day, when you aren't using it, so the repetition need not be about the prior day.
גבול technically means "territory" in Tanach, with border as a secondary, though intimately related, meaning. But I like your take, too.
Do you have a source for your take on תשביתו? That might answer a difficulty with the passuk and still fit with the Gemara, in a way. A literal translation of the passuk might be "Seven days unleavened bread shall ye eat, but on the first day ye shall put sourdough to rest; for any eater of leavened bread, [and] cut off that person will be from Yisrael, from the first day until the seventh day." Most switch the order of the last two phrases so it reads "any eater of leavened bread from the first day until the seventh day, that person will be cut off" but maybe "for any...Yisrael" is parenthetic, explaining why sourdough is forbidden, and the main verse is "Seven days unleavened bread shall ye eat, but on the first day ye shall put sourdough to rest...from the first day until the seventh day." Now you have two "first days" and you can have one be the day before, and say אך divides and translate "Seven days unleavened bread shall ye eat, and for part of the first day ye shall put sourdough to rest...from the first day until the seventh day." Don't know if that fits the Gemara, though.
No source for tashbitu, other than a grammatical analysis (of causitive) and general meaning of $-B-T, like in tishbot, בחריש ובקציר תשבות. About gevul and border vs. territory, yes, someone was telling me that the other day.
Maybe it can be aligned with the gemara, but I'd suspect it would be a big kvetch. The way I envision it is that the rest begins on the first day, when you aren't using it, so the repetition need not be about the prior day.