"Best they honor thee Who honor in thee only what is best." -William Watson, poet (1858-1935)

What does this mean? Is it "they" or "thee" that the restrictive clause "who..." modifies?

Sorry. I racked my brain in vain to figure it out.

I’m learning English. If u find anywhere I can improve my composition, Pls do let me know. Bow.


Do inform me if you see any corrections needed in my written English.