Be my guest

Anyone know the origins of "be my guest"?

It originates in what is suggested by the words. "Be my guest" means "act as though I were your host, enjoy my hospitality." It is similar in this respect to "Make yourself at home," or "have a ball." This latter contains the suggestion that your hospitality is not whole-hearted, as when, for instance, it is compelled by, say, the police, or the landlord. The Oxford English Dictionary says this:

"c. Phr. be my guest: you are welcome to (something); do as you wish.
1955 Amer. Speech x. 302 Be my guest, used when someone asks for something: 'Join me' or 'Go right ahead'. 1962 D. MAYO Island of Sin xiii. 118 Rum? Scotch? Bourbon? Be my guest. 1965 New Statesman 14 May 760/3 'Did you say something, man?' the face asked. I took a deep breath..and then I address the face. 'Not a thing, brother,' I reply, 'not a thing. Be my guest.' . . . "

The last example above exhibits the somewhat nuanced hospitality indicated above, that is, less than enthusiastic.

This term and similar ones are treated in the Archive. Enter "Be my guest" in the search box at the top of the previous page, or go to:

www.phrases.org.uk bulletin_board 47 messages 407.htm

If, on the other hand, you're not talking about the idiomatic meaning of "go ahead", the three words have been friends for a very long time. For example, from "The Affectionate Shepheard" by Richard Barnfield circa 1594:
"Against my birth-day thou shalt be my guest,
Weele have greene-cheeses and fine silly-bubs,
And thou shalt be the chiefe of all my feast,
And I will give thee two fine pretie cubs,
With two yong whelps, to make thee sport withall,
A golden racket, and a tennis-ball."