> Þykist eg ekki af því vaxa þótt eg bíði heiman þræla Haralds konungs og elti þeir oss af eignum vorum eða þiggja af þeim dauða með öllu."
> It seems to me not from it to grow although I wait at home (as?) King Harald's thrall, and they chase us from our possessions or accept from them death altogether."
<vaxa> here "grow greater in fame" (Z4). Paraphrasing a bit: "I do not think that I will grow more famous, even if I wait for King Harald's thralls and they chase us from our possessions, or I meet my death at their hands." <þræla> is genitive plural; the verb <bíða> takes a genitive object to express what is waited for. <heiman> literally "from home", referring to the thralls setting out from their home to do these dastardly deeds.
In Modern Icelandic, the present subjunctive 1st person sg. would be <þiggi>, in Old Icelandic <þiggja>, which makes me think perhaps whoever adapted it to the modern standard spelling overlooked it, thinking it was the infinitive.