Bava Kamma 55A

נאמר בהם ״טוב״? אמר לו: עד שאתה שואלני למה נאמר בהם ״טוב״, שאלני אם נאמר בהן ״טוב״ אם לאו ⁠– שאיני יודע אם נאמר בהן ״טוב״ אם לאו; כלך אצל רבי תנחום בר חנילאי, שהיה רגיל אצל רבי יהושע בן לוי ⁠– שהיה בקי באגדה.

in the context of the mitzva to honor one’s parents, the word good is stated there: “In order that it should be good for you” (Deuteronomy 5:16)? R' Ḥiyya bar Abba said to him: Before you ask me why the word good is stated, ask me if the word good is actually stated there or not, since I am not sufficiently proficient in my knowledge of the biblical verses to remember the precise wording, and I do not know if the word good is stated there or not. Go to R' Tanḥum bar Ḥanilai, who was commonly found at the academy of R' Yehoshua ben Levi, who was an expert in aggada. Perhaps he heard something from him on this matter and can answer your question.

אזל לגביה. אמר ליה: ממנו לא שמעתי, אלא כך אמר לי שמואל בר נחום אחי אמו של רב אחא ברבי חנינא, ואמרי לה אבי אמו של רב אחי ברבי חנינא: הואיל וסופן להשתבר.

R' Ḥanina ben Agil went to him and asked him. R' Tanḥum said to him: I did not hear anything on this matter from R' Yehoshua ben Levi himself. But this is what Shmuel bar Naḥum, the brother of the mother of Rav Aḥa, son of R' Ḥanina, said to me, and some say it was the father of the mother of Rav Aḥai, son of R' Ḥanina: It does not mention the word good in the first tablets, since they were ultimately destined to be broken after the Jews made the Golden Calf.

וכי סופן להשתבר מאי הוי? אמר רב אשי: חס ושלום, פסקה טובה מישראל.

The Talmud asks: And even if it had mentioned the term good, and they were ultimately destined to break, what of it? Rav Ashi said: If this term had been mentioned in the first tablets, all good would have, God forbid, ceased from Israel once they were broken. Therefore, only the second version, which was written after the breaking of the tablets, contains the word good, so that there would always be good for the Jewish people.