Midrasch zu Bereschit 5:5

“…seventy shekels according to the holy shekel…” (Numbers 7:13) Seventy in parallel to the seventy nations which descended from him (from Adam). Another explanation. Why seventy? In parallel to the seventy verses from the beginning of the book of Genesis to the curse of the snake. R’ Pichas said: there are two enemies who were not cursed until seventy verses had been completed about them – the snake and Haman the wicked. Regarding the snake, from “In the beginning…” (Genesis 1:1) until “…cursed be you more than all the cattle…” (Genesis 3:14) is seventy verses. Regarding Haman, from “After these events, King Ahasuerus promoted Haman…” (Esther 3:1) until “And they hanged Haman…” (Esther 7:10) is seventy verses. For the purpose of seventy he was hanged on fifty (cubits of wood). Another explanation. In parallel to the seventy holy names from ‘In the beginning’ until the story of the snake. And if you say there is one more (than seventy) “…and you will be like gods…” (Genesis 3:5) is not a holy name. Another explanation. In parallel to the seventy years before Terach gave birth to Avraham, as it says “And Terach lived seventy years…” (Genesis 11:26) Two people lived in two generations for seventy years. Kenan in the first generation, “And Kenan lived seventy years…” (Genesis 5:12) and Terach in the second generation. Another explanation. Parallel to the seventy days which they wept over Yaakov the pious, as it says “…and the Egyptians wept over him for seventy days.” (Genesis 50:3) Another explanation. Parallel to the seventy days of goodness which the Holy One gave to Israel – seven days of Passover, eight days of Sukkot, Rosh HaShanah, Yom Kippur, Shavuot and the fifty two days of Shabbat in the solar year make seventy. Another explanation. Parallel to the seventy names of the Holy One, the seventy names of Israel, the seventy names of the Torah, the seventy names of Jerusalem. Another explanation. Parallel to the seventy years that Adam took away from his life and gave to David ben Yishai. It was fit that he live for a thousand years, as it says “…for on the day that you eat thereof, you shall surely die.” (Genesis 2:17) And a day to the Holy One is a thousand years, as it says “For a thousand years are in Your eyes like yesterday, which passed, and a watch in the night.” (Psalms 90:4)