'Threescore And Ten Years' in the Bible

to fulfil the word of Jehovah by the mouth of Jeremiah, until the land had enjoyed its sabbaths: for as long as it lay desolate it kept sabbath, to fulfil threescore and ten years.

Then the angel of Jehovah answered and said, O 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 threescore and ten years?