Deuteronomy 32:7

זכר ימות עולם REMEMBER THE DAYS OF OLD — what He did to previous generations who provoked Him to anger, בינו שנות דר ודר [CONSIDER] THE YEARS OF GENERATION AFTER GENERATION — the generation of Enosh over whom He caused the waters of the ocean to flow, and the generations of the flood whom He drowned by flood (cf. Sifrei Devarim 310:1). Another explanation is: If you have not set your attention to the past (i.e. if you fail to remember the days of old, then) בינו שנות דר ודר CONSIDER at least THE YEARS OF GENERATION AND GENERATION so that you become conscious of what might happen in the future — that He has the power to bestow good upon you and to make you inherit the blissful days of Messiah and the world to come (cf. Sifrei Devarim 310:5). שאל אביך ASK THY FATHER — these are the prophets who are termed fathers, as it is stated in the history of Elijah that Elisha exclaimed when Elijah departed, (2 Kings 2:12): “My father, my father, the chariot of Israel!” (cf. Sifrei Devarim 310:3). זקניך THY ELDERS — these are the sages, ויאמרו לך AND THEY WILL TELL THEE the events of the former days:

Remember the days of old consider the years of many generations: ask thy father, and he will recount it to thee; thy elders, and they will tell thee.

זְכֹר֙ יְמ֣וֹת עוֹלָ֔ם בִּ֖ינוּ שְׁנ֣וֹת דֹּר־וָדֹ֑ר        שְׁאַ֤ל אָבִ֙יךָ֙ וְיַגֵּ֔דְךָ זְקֵנֶ֖יךָ וְיֹ֥אמְרוּ לָֽךְ׃