Seventy has a sacred meaning in the Bible that is made up of the factors of two perfect numbers, seven (representing perfection) and ten (representing completeness and God’s law). As such, it symbolizes perfect spiritual order carried out with all power. It can also represent a period of judgment.
70 elders were appointed by Moses (Numbers 11:16). After reading the covenant God gave him to read to the people, Moses took 70 elders, along with Aaron and his sons, up Mount Sinai to have a special meal with God himself (Exodus 24:9 – 11)!
Ancient Israel spent a total number of 70 years in captivity in Babylon (Jeremiah 29:10).
Seventy is also specially connected with Jerusalem. The city kept 70 years of Sabbaths while Judah was in Babylonian captivity (Jeremiah 25:11). Seventy sevens (490 years) were determined upon Jerusalem for it to complete its transgressions, to make an end for sins and for everlasting righteousness to enter into it (Daniel 9:24).