Only there appeared unto them a fire kindled of itself, very dreadful: for being much terrified, they thought the things which they saw to be worse than the sight they saw not.
WEB
but only the glimmering of a self-kindled fire appeared to them, full of fear. In terror, they considered the things which they saw to be worse than that sight, on which they could not gaze.
DRC
But there appeared to them a sudden fire, very dreadful: and being struck with the fear of that face, which was not seen, they thought the things which they saw to be worse:
LXXE
Only there appeared unto them a fire kindled of itself, very dreadful: for being much terrified, they thought the things which they saw to be worse than the sight they saw not.