-Written by David to Joab 2 Samuel 11:14
-King of Syria to king of Israel 2 Kings 5:5, 6
-Rabshakeh to Hezekiah Isaiah 37:9-14
-King of Babylon to Hezekiah Isaiah 39: 1
-Sennacherib to Hezekiah 2 Kings 19: 14
-Of Artaxerxes to Nehemiah Nehemiah 2:7-9
-Open letter from Sanballat to Nehemiah Nehemiah 6:5
-Luke to Theophilus (the books of Luke and Acts) Acts 1 : 1
-Claudius Lysias to Felix Acts 23:25-30
-Letters of intercession by Paul and Philemon on behalf of Onesimus Phm 1 : 1
-Of recommendation 2 Corinthians 3 : 1