Midrasch zu Schemuel II 1:18

(Jos. 10, 13) And the sun stood still .........written in the book of Yashar. What is the book of Yashar? Said R. Chiya b. Aba in the name of R. Jochanan: "This refers to (Genesis) the book in which the birth of Abraham, Isaac, and Jacob, who are named Jesharim (the upright), as it is said (Num. 23, 10) Let me die the death of the righteous Jesharim, etc. And where is it hinted [that such a miracle will occur with Joshua]? From (Gen. 48, 19) And his seed shall become a multitude of nations, i.e., when shall his seed become a multitude of nations? At the time when Joshua stopped the sun. (Jos. 10, 13) And the sun stood still in the midst of the heavens, and hastened not to go down about a whole day. How many hours? Said R. Joshua b. Levi: "Twenty-four hours; it went six [hours] and stopped six, went six, and stopped six, the entire episode lasting a whole day." R. Elazar said: "Thirty-six hours, it went six [hours] and stopped twelve, it went six, and stopped twelve; its stopping time was equal to a whole day [24 hours]." R. Samuel b. Nachmeni said: "Forty-eight, it went six and stopped twelve, went six and stopped twenty-four, for it is said, And it hastened not to go down about a whole day." According to the above, they differ in the additional hours of that day.We are taught in a Baraitha: Just as the sun stopped for Joshua, so also did it stop for Moses. An objection was raised from (Ib. ib. 14) And there was no day like that before it or after it. If you wish, in the time of Moses it stopped for fewer hours, or if you wish, it may be said that in Moses' time there were no hailstones mentioned, as the passage says (Ib. ib. 11) And it came to pass, as they fled from before Israel, etc., that the Lord cast down great stones, and said: To teach the sons of Judah the bow, Behold it is written in the book of Yashar. What does Yashar mean? Said R. Chiya b. Aba in the name of R. Jochanan: "This refers to Genesis [as said above]. And where is it hinted [that Judah will be fighters]? It is written (Gen. 49, 8) Thy hand shall be on the neck of thy enemies. Which is the weapon that needs the hand against the neck? It is the how," R. Elazar, however, maintains that the book of Yashar refers to Deuteronomy. And why is it named Yashar? Because there is a passage (6, 18) And thou shalt do that which is right (Yashar) and good in the eyes of the Lord. And where is the intimation of this? (33, 7) Let the power of his hands. And which is the weapon for which both hands are needed? It is the bow." R. Samuel b. Nachmeni said: "It refers to the book of Judges. And why is it called Yashar? Because therein is written (17, 6) Every man did what seemed right (Yashar) in his eyes. And where is it intimated [in the Biblical text]? (3, 2) To teach them war. And what is the weapon for which teaching is necessary? This is the bow. And whence do we know that this refers to Judah? The passage reads (Ib. 1, 1) Who shall go up for us first against them? And the Lord said: 'Judah shall go up.' "