Can details be given as to how “the integral age of the righteous” teaching arose?

This Q is a follow-up to one I recently asked in Hermeneutics – link - https://hermeneutics.stackexchange.com/questions/80776/does-the-hebrew-of-deuteronomy-312-indicate-that-moses-date-of-death-was-exact/80821#80821 It appears from one answer given there that there is an interesting development of this idea, based on dates of death and birth of significant characters in the Hebrew scriptures, but as Hermeneutics is not for topics, but for examination of biblical texts, my Q there was confined to the text of Deuteronomy 31:2. > "And [Moses] said to them, I am an hundred and twenty years old this > day..." (A. Now, having obtained the answer to that ***(“No, the Hebrew of that text does not indicate that Moses’ date of death was exactly the same as his date of birth, 120 years later”)***, **I wish to explore the topic of how the view regarding "the integral age of the righteous" developed.**