This is now bone of my bones and flesh of my flesh; she shall be called ‘woman,’ for she was taken out of man.” That is why a man leaves his father and mother and is united to his wife, and they become one flesh.
"A wise man who built his house on the rock. And the rain fell, and the floods came, and the winds blew and slammed against that house; and yet it did not fall, for it had been founded on the rock." - Matthew 7: 24-25
Two are better than one, because they have a good return for their labor: If either of them falls down, one can help the other up. But pity anyone who falls and has no one to help them up. Also, if two lie down together, they will keep warm. But how can one keep warm alone?