“was sitting in the King’s Gate.” It was customary for kings and officials to sit in the gate and judge the people of the city and conduct business (e.g., 2 Sam. 19:8; 1 Kings 22:10; 2 Chron. 18:9; Esther 2:21; Jer. 38:7; Dan. 2:49). The fact that Mordecai was sitting in the King’s Gate points out that he was an official or important man of some rank, otherwise he would not have been allowed to sit there.
“assassinate.” The literal Hebrew is an idiom: they sought to “stretch forth a hand against” King Ahasuerus. They wanted to kill him.