Daniel 9:1-3

In the first year of Darius the son of Ahasuerus, of Median descent, who was made king over the kingdom of the Chaldeans— in the first year of his reign, I, Daniel, observed in the books the number of the years which was revealed as the word of the LORD to Jeremiah the prophet for the completion of the desolations of Jerusalem, namely, seventy years. So I gave my attention to the Lord God to seek Him by prayer and supplications, with fasting, sackcloth and ashes.