Daniel 9:2 - Clarke's commentary and critical notes on the Bible

In the first year of his reign I Daniel understood by books the number of the years, whereof the word of the LORD came to Jeremiah the prophet, that he would accomplish seventy years in the desolations of Jerusalem. I Daniel understood by books - The prophecy referred to here is found Jeremiah 25:12; Jeremiah 29:10. The people must have been satisfied of the Divine inspiration of Jeremiah, or his prophecies would not have been so speedily collected nor so carefully preserved. It appears that there was a copy of them then in Daniel's hands.