This is the first example of how it is better not to be alone. You get into an accident and you are alone. Nobody can help you. This may happen, for example, to an old woman who lives alone and who falls down the stairs and breaks her hip. There is no one who can help or call for the right help immediately.
10 For if they fall, one will lift up his fellow. But woe to him who is alone when he falls and has not another to lift him up!