This verse is somewhat obscure and seems like an interpolated amplification of the preceding verse.
VIII
The all-seeing fire which exists hidden in the two sticks, as the foetus is well-guarded in the womb by the mother, (that fire) is to be worshipped day after day by wakeful seekers (after wisdom), as well as by sacrificers. This verily is That.
Fire is called all-seeing because its light makes everything visible. In Vedic sacrifices the altar fire was always kindled by rubbing together two sticks of a special kind of wood called Arani. Because fire was regarded as one of the most perfect symbols of Divine wisdom, it was to be worshipped by all seekers after Truth, whether they followed the path of meditation or the path of rituals.
IX
From whence the sun rises, and whither it goes at setting, upon That all the Devas depend. No one goes beyond That. This verily is That.
X
What is here (in the visible world), that is there (in the invisible); he who sees difference (between visible and invisible) goes from death to death.
XI
By mind alone this is to be realized. There is no difference whatever (between visible and invisible). He who sees difference here (between these) goes from death to death.