'Letters' in the Bible

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

So the couriers went with the letters from the king and his princes throughout all Israel and Judah, and according to the commandment of the king, saying, "You children of Israel, turn again to Yahweh, the God of Abraham, Isaac, and Israel, that he may return to the remnant that have escaped of you out of the hand of the kings of Assyria.

He also wrote letters insulting Yahweh, 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 the God of Hezekiah not deliver his people out of my hand."