Variantly: "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.
"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)."
"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."