Zohar — Sava DeMishpatim (Parashat Mishpatim)
Zohar, Mishpatim 94b
The famous 'Sava DeMishpatim' section of the Zohar is the most extensive kabbalistic treatment of gilgul neshamot (transmigration of souls), describing how souls return to the world in specific conditions, bodies, and families according to their spiritual debts and the rectifications needed — the classical source for divinely-directed soul placement.
וּבְגִין דָּא, נִשְׁמְתָא דְּאִיהִי מִחַיְיבָא בְּגִלְגוּל, אִם הִיא בְּרָתָא דְקוּדְשָׁא בְּרִיךְ הוּא, אִי תֵּימָא דְּאִזְדְבָן בְּגוּפָא נוּכְרָאָה, דְּתַמָּן שֻׁלְטָנוּתָא דְּיֵצֶר הָרָע דְּאִיהוּ מִסִּטְרָא דְּסָמָאֵ"ל. חַס וְשָׁלוֹם. דְּהָא כְּתִיב, (ישעיהו מ״ב:ח׳) אֲנִי יְיָ' הוּא שְׁמִי וּכְבוֹדִי לְאַחֵר לא אֶתֵּן דְּאִיהוּ יֵצֶר הָרָע.
Now as for the soul which is doomed to undergo transmigration, if she is the daughter of the Holy One, blessed be He, we cannot suppose that she is sold to an alien body that is under the domination of the evil spirit emanating from the side of Samael, since it is written: “I am the Lord, that is my name, and my glory will I not give to another” (Isa. 42, 8). Nor is it to be thought that the body which harbours the daughter of the king shall be sold into the power of earthly crowns of defilement.