Isaiah 23:15-16

In the day that the Lord would execute His plan against Tyre, there would be a period of 70 years when Tyre would experience relief from her oppressors. Compare the 70 years of Israel’s captivity in Babylon, probably not the same period. "Like the days of one king" refers to the book of days that kings kept in which they recorded the events of their reigns day by day. The meaning is similar to "as a hired man would count" (Isaiah 16:14; Isaiah 21:16), namely, that these would be 70 literal, fixed years. Tyre did experience such a period of respite following the campaigns of Sennacherib in 701 B.C. During the next 70 years, Assyria was in decline and did not pay much attention to Tyre. Another view is that the 70 years followed Nebuchadnezzar’s invasion. A third view is that the 70 years are the same as those of the Babylonian captivity of Israel (Delitzsch, 1:414, 420). A fourth interpretation is that 70 is a round number and indicates simply an extended period of time. Consequently Tyre regained some of her former strength.