Midras Hakim-hakim 3:16: Midrash Tanchuma Buber & Midrash Tanchuma

Another interpretation (of Gen. 49:27): BENJAMIN IS A RAVENOUS WOLF. < The verse > speaks of its judge, Ehud.⁷²Cf. Gen. R. 99:3. What is written (in Jud. 3:16)? SO EHUD MADE HIMSELF A SWORD, AND IT HAD TWO EDGES, i.e., he was busy with Torah, which (in Ps. 149:6) is called A TWO-EDGED SWORD. AND (according to Jud. 3:16) IT HAD TWO EDGES (literally: TWO MOUTHS) because it consumes in two worlds, in this world and in the world to come.

Another interpretation (of Jud. 3:16): SO EHUD MADE HIMSELF A SWORD and put it ON HIS RIGHT THIGH. Coming in to Eglon, he said to him: I HAVE A WORD FROM GOD FOR YOU {THE KING}; SO HE AROSE FROM HIS SEAT. The Holy One said: You have imparted glory to me and risen from your seat for the sake of my glory. By your life, I will raise up a daughter from you from whom a son shall arise, and I will seat him upon my throne. This woman was Ruth the Moabite, from whom arose Solomon, of whom it is written (in I Chron. 29:23): THEN SOLOMON SAT UPON THE THRONE OF THE LORD. What is written (in Jud. 3:21)? THEN EHUD PUT OUT HIS LEFT HAND AND TOOK THE SWORD FROM HIS RIGHT THIGH. (Cf. Gen. 49:27, cont.:) IN THE MORNING HE DEVOURS THE PREY. (Jud. 3:21, cont.:) AND HE THRUST IT INTO HIS BELLY. (Cf. Gen. 49:27, cont.:) AND AT EVENING HE DIVIDES THE SPOIL.

In the Book of Judges, it is written concerning Ehud: And Ehud made him a sword which had two edges (ibid. 3:16). This indicates that he would have a share in two worlds because he had studied the law, about which it is stated: A two-edged sword in their hand (Ps. 149:6). Hence he was privileged to enjoy the fruits of this world and the hereafter.