'Letters' in the Bible

And Hezekiah sent to all Israel and Judah, and wrote letters also to Ephraim and Manasseh, that they should come to the house of Jehovah at Jerusalem, to keep the passover unto Jehovah, the God of Israel.

So the posts went with the letters from the king and his princes throughout all Israel and Judah, and according to the commandment of the king, saying, Ye children of Israel, turn again unto Jehovah, the God of Abraham, Isaac, and Israel, that he may return to the remnant that are escaped of you out of the hand of the kings of Assyria.

He wrote also letters, to rail on Jehovah, the God of Israel, and to speak against him, saying, As the gods of the nations of the lands, which have not delivered their people out of my hand, so shall not the God of Hezekiah deliver his people out of my hand.