Help with older English couplet
Solution 1:
This is "old" in the sense that it was transcribed before English spelling was totally standardized.
The two written versions on offer:
Be war or ye be wo; Knoweth your frend from your foo
Be ware ere ye be woo; Know your friend from your foe
can be subsumed into a modern English translation as
- Beware or you'll be woe; know your friend from your foe.
You'll be woe is no longer an idiom (though You be( )ware still is), but
it clearly means the same thing as Woe betide you -- i.e, "Bad luck; sorry about that."