גַּ֛ם אִם־יִשְׁכְּב֥וּ שְׁנַ֖יִם וְחַ֣ם לָהֶ֑ם וּלְאֶחָ֖ד אֵ֥יךְ יֵחָֽם׃
Again, if two lie together, then they have warmth; but how can one be warm alone?
Read kabbalistic (mystical) interpretation of Ecclesiastes 4:11: and classical mystical sources.