“What is the Book of Jasher/Jashar ,should it be in the Bible?”……Also known as the “Book of the Upright One” in the Greek Septuagint and the “Book of the Just Ones” in the Latin Vulgate, the Book of Jasher was probably a collection or compilation of ancient Hebrew songs and poems praising the heroes of Israel and their exploits in battle. The Book of Jasher is mentioned in Joshua when the Lord stopped the sun in the middle of the day during the battle of Beth Horon.

Joshua 10:12-13On the day the Lord gave the Israelites victory over the Amorites, Joshua prayed to the Lord in front of all the people of Israel. He said, “Let the sun stand still over Gibeon,    and the moon over the valley of Aijalon.” So the sun stood still and the moon stayed in place until the nation of Israel had defeated its enemies. Is this event not recorded in The Book of Jashar? The sun stayed in the middle of the sky, and it did not set as on a normal day.

It is also mentioned in 2 Samuel as containing the song or lament of the bow, that mournful funeral song which David composed at the time of the death of Saul and Jonathan.

2 Samuel 1:18-27and he commanded that it be taught to the people of Judah. It is known as the Song of the Bow, and it is recorded in The Book of Jashar. Your pride and joy, O Israel, lies dead on the hills! Oh, how the mighty heroes have fallen! Don’t announce the news in Gath, don’t proclaim it in the streets of Ashkelon,…or the daughters of the Philistines will rejoice and the pagans will laugh in triumph.O mountains of Gilboa,let there be no dew or rain upon you, nor fruitful fields producing offerings of grain.For there the shield of the mighty heroes was defiled; the shield of Saul will no longer be anointed with oil. The bow of Jonathan was powerful, and the sword of Saul did its mighty work.They shed the blood of their enemies and pierced the bodies of mighty heroes. How beloved and gracious were Saul and Jonathan! They were together in life and in death.They were swifter than eagles,stronger than lions.…O women of Israel, weep for Saul,for he dressed you in luxurious scarlet clothing,…in garments decorated with gold. Oh, how the mighty heroes have fallen in attle! Jonathan lies dead on the hills. How I weep for you, my brother Jonathan! Oh, how much I loved you!And your love for me was deep,deeper than the love of women! Oh, how the mighty heroes have fallen!Stripped of their weapons, they lie dead.

……The question is, if the Book of Jasher is mentioned in the Bible, why was it left out of the canon of Scripture? We know that God directed the authors of the Scriptures to use passages from many and various extra-biblical sources in composing His Word. The passage recorded in Joshua 10:3is a good example. In recording this battle, Joshua included passages from the Book of Jasher not because it was his only source of what occurred, but rather he was stating in effect, “If you don’t believe what I’m saying, then go read it in the Book of Jasher. Even that book has a record of this event.”……There are other Hebrew works that are mentioned in the Bible that God directed the authors to use. Some of these include the Book of the Wars of the Lord

“the town of Waheb in the area of Suphah, and the ravines of the ArnonRiver,

And in 1 Chronicles, the Book of Samuel the Seer, Nathan the Prophet, and Gad the Seer are mentioned ;

1 Chronicles 29:29All the events of King David’s reign, from beginning to end, are written in The Record of Samuel Seer, The Record of Nathan the Prophet, and The Record of Gad the Seer.

Also, there are the Acts of Rehoboam and the Chronicles of the Kings of Judah

1 Kings 14:29The rest of the events in Rehoboam’s reign and everything he did are recorded in The Book of the History of the Kings of Judah

We also know that Solomon composed more than a thousand songs

1 Kings 4:32He composed some 3,000 proverbs and wrote 1,005 songs.

yet only two are preserved in the book of Psalms (72 and 127).

Writing under the inspiration of the Holy Spirit in the New Testament, Paul included a quotation from the Cretan poet Epimenides

Titus 1:12Even one of their own men, a prophet from Crete, has said about them, “The people of Crete are all liars, cruel animals, and lazy gluttons.”This quotation is from Epimenides of Knossos.

and quoted from the poets Epimenides and Aratus in his speech at Athens

Acts 17:28 For in him we live and move and exist. As some of your own poets have said, ‘We are his offspring.’. ……The point is that the divine Author of the Bible used materials chosen from many different sources, fitting them into His grand design for the Scriptures. We must understand that history as recorded in the Bible did not occur in isolation. The people mentioned in the Bible interacted with other people. For example, though the Bible is clear that there is only one God, the Bible mentions a number of the gods people worshipped both within Israel and in the nations around.

Similarly, as in Acts 17:28 and Titus 1:12, we sometimes find secular writers being quoted. This doesn’t mean that these quoted writers were inspired. It simply means they happened to say something that was useful in making a point.…There is no mention of the Book of Jasher in the Bible after the time of David. However, there is a book by that title today, although it is not the same book. It is an eighteenth-century forgery that alleges to be a translation of the “lost” Book of Jasher by Alcuin, an eighth-century English scholar.

There is also a more recent book titled “The Book of Jashar” by science-fiction and fantasy writer Benjamin Rosenbaum.

This book is a complete work of fiction.…Another book by this same name, called by many “Pseudo-Jasher,” while written in Hebrew, is also not the “Book of Jasher” mentioned in Scripture. It is a book of Jewish legends from the creation to the conquest of Canaan under Joshua, but scholars hold that it did not exist before AD 1625. In addition, there are several other theological works by Jewish rabbis and scholars called

“SeferhaYashar,” but none of these claims to be the original Book of Jasher.……In the end, we must conclude that the Book of Jasher mentioned in the Bible was lost and has not survived to modern times. All we really know about it is found in the two Scripture quotations mentioned earlier. The other books by that title are mere fictions or Jewish moral treatises.