Ecclesiastes 4:9-12  NAS          

Two are better than one because they have a good return for their labor.  For if either of them falls, the one will lift up his companion.  But woe to the one who falls when there is not another to lift him up.  Furthermore, if two lie down together they keep warm, but how can one be warm alone?  And if one can overpower him who is alone, two can resist him.  A cord of three strands is not quickly torn apart.