Sifrei Devarim 310

¹(Devarim 32:7) "Remember the days of yore": Remember what I did with the first generations: what I did with the men of the generation of the flood; what I did with the men of the generation of hapalagah (the tower of Bavel); what I did with the men of the generation of Sodom and Amorah. ²"Reflect upon the years of generation upon generation": There is no generation where there are no men like those of the generations of the men of the flood; where there are no men like those of the generation of hapalagah and the men of Sodom — but each is judged according to his acts. ³"Ask your father and he will tell you": These are the prophets, viz. (II Kings 2:12) "And Elisha saw (Eliyahu the prophet) and cried 'My father! My father!'" ⁴"your elders and they will tell you": These are the elders, viz. (Bamidbar 11:16) "Gather unto Me seventy men from the elders of Israel." ⁵Variantly: "Remember the days of the world ": He said to them: Whenever the L-rd brings afflictions upon you, remember how many benefactions and consolations He is destined to accord you in the world to come. ⁶"Reflect upon the years of generation upon generation": This is the generation of the Messiah, which contains three generations, viz. (Psalms 72:5) "They (Israel, in the days of the Messiah) will fear You before the sun and the moon, generation (1) generations (2)." ⁷"Ask your Father and He will tell you": In the future, Israel are destined to see and hear from the mouth of the Holy One Blessed be He, viz. (Isaiah 30:21) "And your ears will hear a word from behind you ([in context: from the mouth of the L-rd]), saying, etc." And (Isaiah, Ibid . 20) "And your Teacher will no longer be hidden behind His garment, and your eyes will see your Teacher." ⁸"your elders, and they shall say it to you": what I showed the elders in the mountain," (Sinai, at the giving of the Torah), viz. (Shemoth 24:1) "And to Moses He said: Go up to the L-rd, you and Aaron, Nadav and Avihu, and seventy from the elders of Israel… ( Ibid . 10) And they saw the G-d of Israel" (and so, in time to come.)