Bible Dictionary
JASHAR, BOOK OF
The Book of Jashar, or Book of the Upright, was an ancient Hebrew collection of national or religious songs. The Old Testament quotes it in connection with Joshua’s battle and David’s lament for Saul and Jonathan.
Biblical Usage
The Old Testament refers to it in connection with Joshua’s command concerning the sun and moon and with David’s lament over Saul and Jonathan. A possible third quotation has been suggested in Solomon’s words about dwelling in thick darkness, but this is uncertain.