Automatic credit card charges on shabbat
ואלו הן משום מצוה לא מקדישין ולא מעריכין ולא מחרימין: גזרה משום מקח וממכר:
§ It was taught in the mishna: And the following are notable because of the full-fledged mitzva involved in them, yet are prohibited on Shabbat: One may not consecrate, nor take a valuation vow, nor consecrate objects for use by the priests or the Temple. The Gemara explains: All these cases are prohibited because of a decree due to their similarity to commerce. These acts, which all involve the transfer of ownership to the Temple treasury, resemble commerce, which is prohibited on a Festival.

(ב) אֲבוֹת מְלָאכוֹת אַרְבָּעִים חָסֵר אֶחָת. הַזּוֹרֵעַ. וְהַחוֹרֵשׁ. וְהַקּוֹצֵר. וְהַמְעַמֵּר. הַדָּשׁ. וְהַזּוֹרֶה. הַבּוֹרֵר. הַטּוֹחֵן. וְהַמְרַקֵּד. וְהַלָּשׁ. וְהָאוֹפֶה. הַגּוֹזֵז אֶת הַצֶּמֶר. הַמְלַבְּנוֹ. וְהַמְנַפְּצוֹ. וְהַצּוֹבְעוֹ. וְהַטּוֹוֶה. וְהַמֵּסֵךְ. וְהָעוֹשֶׂה שְׁנֵי בָתֵּי נִירִין. וְהָאוֹרֵג שְׁנֵי חוּטִין. וְהַפּוֹצֵעַ שְׁנֵי חוּטִין. הַקּוֹשֵׁר. וְהַמַּתִּיר. וְהַתּוֹפֵר שְׁתֵּי תְפִירוֹת. הַקּוֹרֵעַ עַל מְנָת לִתְפֹּר שְׁתֵּי תְפִירוֹת. הַצָּד צְבִי. הַשּׁוֹחֲטוֹ. וְהַמַּפְשִׁיטוֹ. הַמּוֹלְחוֹ, וְהַמְעַבֵּד אֶת עוֹרוֹ. וְהַמּוֹחֲקוֹ. וְהַמְחַתְּכוֹ. הַכּוֹתֵב שְׁתֵּי אוֹתִיּוֹת. וְהַמּוֹחֵק עַל מְנָת לִכְתֹּב שְׁתֵּי אוֹתִיּוֹת. הַבּוֹנֶה. וְהַסּוֹתֵר. הַמְכַבֶּה. וְהַמַּבְעִיר. הַמַּכֶּה בַפַּטִּישׁ. הַמּוֹצִיא מֵרְשׁוּת לִרְשׁוּת. הֲרֵי אֵלּוּ אֲבוֹת מְלָאכוֹת אַרְבָּעִים חָסֵר אֶחָת:

(2) This fundamental mishna enumerates those who perform the primary categories of labor prohibited on Shabbat, which number forty-less-one. They are grouped in accordance with their function: One who sows, and one who plows, and one who reaps, and one who gathers sheaves into a pile, and one who threshes, removing the kernel from the husk, and one who winnows threshed grain in the wind, and one who selects the inedible waste from the edible, and one who grinds, and one who sifts the flour in a sieve, and one who kneads dough, and one who bakes. Additional primary categories of prohibited labor are the following: One who shears wool, and one who whitens it, and one who combs the fleece and straightens it, and one who dyes it, and one who spins the wool, and one who stretches the threads of the warp in the loom, and one who constructs two meshes, tying the threads of the warp to the base of the loom, and one who weaves two threads, and one who severs two threads for constructive purposes, and one who ties a knot, and one who unties a knot, and one who sews two stitches with a needle, as well as one who tears a fabric in order to sew two stitches. One who traps a deer, or any living creature, and one who slaughters it, and one who flays it, and one who salts its hide, a step in the tanning process, and one who tans its hide, and one who smooths it, removing hairs and veins, and one who cuts it into measured parts. One who writes two letters and one who erases in order to write two letters. One who builds a structure, and one who dismantles it, one who extinguishes a fire, and one who kindles a fire. One who strikes a blow with a hammer to complete the production process of a vessel (Rabbeinu Ḥananel), and one who carries out an object from domain to domain. All these are primary categories of labor, and they number forty-less-one.

אֶלָּא הָכָא בְּהָא קָמִיפַּלְגִי: בֵּית שַׁמַּאי סָבְרִי בִּיטּוּל רְשׁוּת מִיקְנֵא רְשׁוּתָא הוּא, וּמִיקְנֵא רְשׁוּתָא בְּשַׁבָּת — אָסוּר. וּבֵית הִלֵּל סָבְרִי אִסְתַּלּוֹקֵי רְשׁוּתָא בְּעָלְמָא הוּא, וְאִסְתַּלּוֹקֵי רְשׁוּתָא בְּשַׁבָּת — שַׁפִּיר דָּמֵי.
Rather, the Gemara rejects Ulla’s explanation and states that here they disagree over the following: Beit Shammai hold that renunciation of a domain is equivalent to acquisition of a domain, and acquisition of a domain is prohibited on Shabbat. And Beit Hillel hold that it is merely withdrawal from a domain, and withdrawal from a domain seems well on Shabbat, i.e., it is permitted. As such, there is no reason to prohibit renunciation as a form of acquisition, which is prohibited as a part of a decree against conducting commerce on Shabbat.
Another central topic relates to the purchase of food products. Commercial activity is prohibited on a Festival as it is on Shabbat. Although commerce is not itself a prohibited labor, it can lead to the performance of many labors. This restriction against trade on Shabbat and Festivals dates back to the time of the prophets. The question is whether a way can be found to allow a person to take items from a friend's home or from a shopkeeper's store, without violating the prohibition against commerce on a Festival. These dilemmas and related matters are the essential issues addressed in this chapter.