Two people are better off than one, for they can help each other succeed.
If one person falls, the other can reach out and help. But someone who falls alone is in real trouble.
Likewise, two people lying close together can keep each other warm. But how can one be warm alone?
A person standing alone can be attacked and defeated, but two can stand back-to-back and conquer. Three are even better, for a triple-braided cord is not easily broken.