Dagger in the Bible

Judges 3:16-22 But Ehud made him a dagger which had two edges, of a cubit length; and he did gird it under his raiment upon his right thigh. 17 And he brought the present unto Eglon king of Moab: and Eglon was a very fat man. 18 And when he had made an end to offer the present, he sent away the people that bare the present. 19 But he himself turned again from the quarries that were by Gilgal, and said, I have a secret errand unto thee, O king: who said, Keep silence. And all that stood by him went out from him. ...