Daniel's prayer and the seventy weeks
Daniel understood from Jeremiah that Jerusalem's seventy years of desolation were nearing completion and confessed the nation's sin. Gabriel came with the prophecy of seventy weeks concerning the city, the coming Anointed One, and the completion of God's purposes (Daniel 9:1-27).
First year of Darius the Mede, after Babylon's fall
1In the first year of Darius son of Xerxes, a Mede by descent, who was made ruler over the kingdom of the Chaldeans— 2in the first year of his reign, I, Daniel, understood from the sacred books, according to the word of the LORD to Jeremiah the prophet, that the desolation of Jerusalem would last seventy years. 3So I turned my attention to the Lord God to seek Him by prayer and petition, with fasting, sackcloth, and ashes.