That's not what the Bible says to do at all, that's the cherry-picked version. It says; "You have heard that it was said, ‘Eye for eye, and tooth for tooth.’ But I tell you, do not resist an evil person. If anyone slaps you on the right cheek, turn to them the other cheek also." It doesn't "instruct" anything, it merely states that you take on an evil person face to face, and if he slaps you on the right cheek, show no fear and present him the other as well.