According to the Bible, Ehud stabbed Eglon, King of Moab.
The story appears in Judges 3. Eglon had led a Moabite alliance that oppressed the Israelites for 18 years. Ehud, described as a left-handed Benjaminite, was chosen to deliver Israel's tribute. He concealed a short, double-edged sword on his right thigh, where it was less likely to be discovered.
After presenting the tribute, Ehud returned to Eglon's private chamber and claimed to have a secret message from God. When the king dismissed his attendants, Ehud drew the sword and struck him. He escaped while Eglon's servants assumed the king was using the chamber privately.
A common mix-up is confusing Ehud with other biblical judges such as Othniel, Deborah, Gideon, or Samson. Ehud is specifically the second judge named in the Book of Judges and is remembered for freeing Israel from Moabite control. The account says Israel then experienced 80 years of peace.