Lost Book of Jasher

The Book of Jasher (also, Jashar) or the Book of the Upright or the Book of the Just Man (Hebrew: סֵפֶר הַיׇּשׇׁר‎; transliteration: sēfer hayyāšār) is an unknown book mentioned in the Hebrew Bible. The translation "Book of the Just Man" is the traditional Greek and Latin translation, while the transliterated form "Jasher" is found in the King James Bible, 1611.

The book appears to be referenced from around the reign of David. 2 Samuel 1:18 states:

David's lament for Jonathan immediately follows. The King James Version of the English Bible has the phrase "the use of" in italics, showing that it is material the translator(s) added in order to render the original text into what they considered understandable and comfortable English. Other versions, such as the English Standard Version, indicate that what David taught the people was The Bow, that is, a poetic lament regarding the death of Saul and Jonathan. If the interpretation offered in the ESV footnote is to be accepted, then The Bow is a lament or a tune that was — at the time of the composition of the Book of Samuel — also included in the extra-canonical Book of Jashar.

The Book of Jasher is also mentioned in the Biblical Book of Joshua amid the descriptions of Joshua's military exploits in the land of Canaan, specifically after Adoni-zedek, king of Jerusalem, and his allies attacked Gibeon for allying themselves with Israel and Joshua and the Israelites came to Gibeon's aid (Joshua 9-10). When "YHWH gave the Amorites over to the sons of Israel", Joshua told the sun to stand still over Gibeon and the moon to stand still over Valley of Aijalon (Joshua 9:1-2). Then the Book of Joshua 10:13 states:

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