Jasher

"Upright. "The Book of Jasher," rendered in the LXX. "the Book of" "the Upright One," by the Vulgate "the Book of Just Ones," was" "probably a kind of national sacred song-book, a collection of" "songs in praise of the heroes of Israel, a "book of golden" "deeds," a national anthology. We have only two specimens from" "the book, (1) the words of Joshua which he spake to the Lord at" "the crisis of the battle of Beth-horon (Josh. 10:12, 13); and" "(2) "the Song of the Bow," that beautiful and touching mournful" elegy which David composed on the occasion of the death of Saul and Jonathan (2 Sam. 1:18-27).

Definition of Jasher:
"righteous; upright"