Psalms 78:2 Midrash

אֶפְתְּחָ֣ה בְמָשָׁ֣ל פִּ֑י אַבִּ֥יעָה חִ֝יד֗וֹת מִנִּי־קֶֽדֶם׃

I will open my mouth with a parable; I will utter dark sayings concerning days of old;