I am guessing that you are asking why people get married? There are a few reasons. First off, because it is a commitment you make to someone that is meant to last a lifetime. If you are not married, a mother and child do not share a last name and if something happened to a spouse, you could not receive benefits. The biggest reason you should get married is because that is what God has intended for us. Our society has perverted the idea of marriage and what is right. It is sinful to have sex outside of marriage, and if you choose not to get married and remain abstinent there is nothing wrong with that. However, marriage is the only acceptable time, in God's eye, to do these things. Marriage is a wonderful thing. Sadly though more and more people are getting married with the idea that if it doesn't work just get divorced. Marriage is a lifelong commitment. "For better or worse" means exactly that, through the good and bad you stay with your spouse.