> að bjóða trú rétta.
> to preach (the) right faith.

Yes: the right or correct faith/religion. 'trú rétta' is feminine
accusative singular.

> hins skjálga
> the (squint-eyed, MM/HP)

http://lexicon.ff.cuni.cz/png/oi_cleasbyvigfusson/b0552.png