"Be well."

"Be well." This is the second time I've heard this phrase (in Canada, specifically in Quebec) in two weeks. The first was when it was used in conversation instead of "Goodbye," "Bye-bye," "Take care," etc. And the second time was today, in text, when someone used it as a complimentary close in an e-mail.

My question is, Is this a neologism or an old phrase? If not a recent phrase, could an origin be explained. Thank you.