'Seventy' in the Bible

In the first year of his rule, I, Daniel, saw clearly from the books the number of years given by the word of the Lord to the prophet Jeremiah, in which the making waste of Jerusalem was to be complete, that is, seventy years.

Seventy weeks have been fixed for your people and your holy town, to let wrongdoing be complete and sin come to its full limit, and for the clearing away of evil-doing and the coming in of eternal righteousness: so that the vision and the word of the prophet may be stamped as true, and to put the holy oil on a most holy place.