Ecclesiastes 4:9-12

Two are better than one, for they can help each other in their work. If one of them falls down, the other can help them up, but how sad it is for someone who falls down and doesn't have anyone to help them up. In the same way, if two people lie down together, they keep each other warm, but you can't keep yourself warm if you're alone. Someone fighting against one other person may win, but not if they are fighting against two. A cord made of three strands can't be torn apart quickly.