“For the pauper will not cease from the midst of the land (Deuteronomy 15:11)—it was taught, Rabbi El’azar ha-Qappar says: Always will a man seek mercy over this measure, since if he does not come [to poverty] his son comes [to poverty]. And if his son does not come [to poverty], the son of his son comes [to poverty], as is said, בִּגְלַל (Bigelal), because for this thing (ibid., 10). The House of Rabbi Yishma’el taught: It is a גַּלְגָּל (galggal), wheel, that חוֹזֵר (ḥozer), turns, in the world” (BT Shabbat 151b).
“Seeing a גּוּלְגּוֹלֶת (gulggolet), skull, floating on the water, [Hillel] said: ‘Because you drowned others, they drowned you, and those who drowned you will themselves eventually be drowned’ [in גָּלוּת (galut), exile]” (M Avot 2:7).
“Rabbi Yirmeyah son of Abba said in the name of Rabbi Yoḥanan, ‘Whoever walks four cubits in the land of Israel is assured to be a son of the world to come.’ Now… aren’t the righteous outside the Land going to be revived? Rabbi Il’a said, ‘By גִּלְגּוּל (gilggul), rolling.’ Rabbi Abba Sala the Great objected, ‘Rolling will be painful to the righteous!’” (BT Ketubbot 111a, cf. Zohar 1:113b–114b [MhN], 131a).
“Now this is the mystery of גִּלְגּוּל (gilggul), rolling: גַּלְגָּל (Galggal), a wheel, does not תְּנוּעָה (tenu’ah), move, without אַמַּת הַמַּיִם (ammat ha-mayim), an aqueduct. So too, an aqueduct is the mystery of the letter ו (vav), by means of which the wheel rolls. And the secret of the matter: No wheel has motion without an aqueduct, so too a wheel, which is י (yod), has no movement without an aqueduct which is ו (vav)….
And moreover י (yod) is נְקֻדָּה (nequddah), a point; ו (vav) גַּלְגַּל (galggal), a wheel. And there is no movement in the wheel at the six spokes [lit., סִטְרִין (sitrin), sides]—reckoning ו׳ (six)—only at the point” (Zohar 3:215b, 223b Ra’aya Meheimna Pineḥas).