Parashas Shemos
וַתַּ֥הַר הָאִשָּׁ֖ה וַתֵּ֣לֶד בֵּ֑ן וַתֵּ֤רֶא אֹתוֹ֙ כִּי־ט֣וֹב ה֔וּא וַֽתִּצְפְּנֵ֖הוּ שְׁלֹשָׁ֥ה יְרָחִֽים׃
The woman conceived and bore a son; and when she saw how beautiful he was, she hid him for three months.
Torah Temimah points to baraisa — Sotah 12a (verified).
כי טוב הוא — תניא, ר׳ מאיר אומר טוב שמו, ר׳ יהודה אומר טוביה שמו, ר׳ נחמיה אומר הגון לנביאות הוא, אחרים אומרים שנולד מהול, וחכמים אומרים שנתמלא כל הבית אורה.
English: “That he was good” — it was taught: R’ Meir said “Tov was his name”; R’ Yehudah said “Toviyah was his name”; R’ Nechemyah said he was fit for prophecy; others said he was born circumcised; and the Sages said the whole house was filled with light.
Custom — multiple midrashic readings of tov.
Chazal offer several complementary explanations of the goodness perceived at Moshe’s birth, culminating in the tradition that light filled the house.