Parashas Haazinu · Passuk 32:7
Torah Temima points to Shabbat 23a on the source for the Chanukah blessing.
English: Over the Chanukah lamp one recites the blessing “…Who has sanctified us with His commandments and commanded us to kindle the Chanukah lamp.” And where did He command us? Rav Nachman said: “Ask your father and he will tell you, your elders and they will say to you.”
A source for rabbinic mitzvot drawn from the authority of tradition transmitted by the elders.
Even commandments that are not explicit in the Written Torah rest on the authority of the chain of tradition. The verse “ask your father… your elders” is the warrant for the blessing over Chanukah lights and, by extension, for the binding force of the oral tradition.