Daniel learned from the books of the prophets, especially from Jeremiah, that the desolation of Jerusalem would continue seventy years, which were drawing to a close. God's promises are to encourage our prayers, not to make them needless; and when we see the performance of them approaching, we should more earnestly plead them with God.
Matthew Henry's Commentary on Daniel 9:1
Commentary on Daniel 9:1-3
(Read Daniel 9:1-3)
Daniel learned from the books of the prophets, especially from Jeremiah, that the desolation of Jerusalem would continue seventy years, which were drawing to a close. God's promises are to encourage our prayers, not to make them needless; and when we see the performance of them approaching, we should more earnestly plead them with God.