The only ones who can shoot are those who are prepared to be shot.
「撃っていいのは撃たれる覚悟のある奴だけだ」は英語で「The only ones who can shoot are those who are prepared to be shot.」と言います。「shoot」より「fire」でも大丈夫です。
"The only ones who can shoot are those who are prepared to be shot." is a famous line from Lelouch.
「撃っていいのは撃たれる覚悟のある奴だけだ」はルルーシュの名言ですね。