Because we need a witness to our lives. There's a billion people on the planet. I mean, what does any one life really mean? But in a marriage,  you're promissing to care about everything-the good things, the bad things, the terrible things, the mundane(日常的，枯燥的) things...All of it, all the time, every day. You're saying, "Your life will not go unnoticed, because I will be your witness."

God won't ask what you did to help yourself, but will ask what you did to help others.