'Seventy Years' in the Bible

And the angel of Jehovah answered and said, Jehovah of hosts, how long wilt thou not have mercy on Jerusalem and on the cities of Judah, against which thou hast had indignation these seventy years?

Speak unto all the people of the land, and to the priests, saying, When ye fasted and mourned in the fifth and seventh month, even those seventy years, did ye at all fast unto me, even to me?

When ye fasted with mourning in the fifth and in the seventh months -- even these seventy years -- did ye keep the fast to Me -- Me? And when ye eat, and when ye drink, is it not ye who are eating, and ye who are drinking?