Ecclesiastes 4:9-12

Two are better off than one, because together they can work more effectively. If one of them falls down, the other can help him up. But if someone is alone and falls, it's just too bad, because there is no one to help him. If it is cold, two can sleep together and stay warm, but how can you keep warm by yourself? Two people can resist an attack that would defeat one person alone. A rope made of three cords is hard to break.