From Njal 36 beginning:

> "og fer þér illa þar sem eg hefi mælt
> `and (it) goes to you badly (reflects badly on you) where I have spoken

From Njal 36 part 2:

> Og væntir mig að þér fari vel en þó munt þú verða mjög að þreyttur."
> spoken-with-each-other well (been on good terms?) . And (it)

gives-hope to me that (it will) go well for you but still you will be
much tested (sorely tried)

In each of these examples, isn't the sense of the expression 'e-m ferr
vel/illa' rather "one acts/behaves well/badly"? -- the person who acts
being in the dative. This is how Magnuús Magnússon and Hermann
Pálsson take it, and the idiom is defined thus by Zoega under 'fara' (10).