Nú hefk mart
í miði greipat
burar Bors
Búra arfa.
Nú hefk greipat mart í miði burar Bors, arfa Búra.
Now I have included many things in the mead of the son of Borr <mythical being> [= Óðinn > POEM], the heir of Búri <mythical being> [= Óðinn].
case: dat.