כְּתִיב אַפִּינְקָסֵיהּ דְּרַבִּי יְהוֹשֻׁעַ בֶּן לֵוִי: הַאי מַאן דִּבְחַד בְּשַׁבָּא, יְהֵי גְּבַר וְלָא חֲדָא בֵּיהּ
After citing relevant halakhot written in the notebooks of various Sages, the Talmud relates:
It was written in Rabbi Yehoshua ben Levi’s notebook:
One who was born on the first day of the week, Sunday, will be a person and there will not be one in him.The Gemara asks: What is the meaning of the phrase: There will not be one in him? If you say that there is not one quality for the best, that cannot be, as Rav Ashi said: I was born on the first day of the week, and one cannot say that there was nothing good about him. Rather, it must mean that there is not one quality for the worst. Didn’t Rav Ashi say: I and Dimi bar Kakuzta were both born on the first day of the week. I became a king, the head of a yeshiva, and he became the head of a gang of thieves, clearly a negative quality. Rather, one born on a Sunday is either completely for the best or completely for the worst. What is the reason for this? It is because both light and darkness were created on the first day of Creation.
One who was born on the second day of the week, Monday, will be a short-tempered person. What is the reasonfor this? It is because on that day, the second day of Creation, the upper and lower waters were divided. Therefore, it is a day of contentiousness.
One who was born on the third day of the week will be a rich man and a promiscuous person. What is the reasonfor this? It is because on that day, the third day, vegetation was created. It grows abundantly but is also mixed together without boundaries between the grass and the plants.
One who was born on the fourth day of the week will be a wise and enlightened person. What is the reason for this? It is because the heavenly lights were hung in the heavens on that day, and wisdom is likened to light.One who was born on the fifth day of the week will be a person who performs acts of kindness. What is the reason for this? It is because on that day the fish and fowl were created, and they do not receive their sustenance by performing work for people. They are sustained by the kindness of God alone.
One who was born on the sixth day of the week will be a seeker. Rav Naḥman bar Yitzḥak said that this means that he will be one who seeks out mitzvot [does good deeds or refrains from bad ones according to Torah values], as most of the activity on Friday involves preparation for Shabbat.
One who was born on Shabbat will die on Shabbat, because they desecrated the great day of Shabbat on his behalf. Rava bar Rav Sheila said: And he will be called a person of great sanctity because he was born on the sacred day of Shabbat.
—from Sefaria