Formal:
* God be wiþ eow. (God be with you.)
* Fareþ wel. (Farewell.)
* Hwæt, geondweorp þine feohte, and wæs þu gesund. (Well, finish your task, and be you well.)
Informal:
* Wæs hal. (Be well.)
* Gode beo þanc. (Thanks be to God.)
* God be wiþ þe. (God be with you.) (Used for a single friend)
Other options:
* Hwæt, geondweorp þine gewyrht. (Well, finish your work.)
* Beo þu gesund. (Be you well.)
* Se þe wæs þu geondweorp þine weorc. (May you finish your work.)
Important notes:
* Old English was a highly inflected language, so the exact wording would depend on the grammatical context.
* These phrases are not necessarily literal translations of modern English expressions. They convey similar sentiments but with a different linguistic style.
Examples:
* "God be wiþ eow, mine freond." (God be with you, my friends.)
* "Fareþ wel, and ne forgæt ge me næfre." (Farewell, and never forget me.)
* "Wæs hal, and beo þu gesund." (Be well, and be you healthy.)
You can use these phrases to add a touch of historical authenticity to your writing or speech.