Their eyes failing represents their seeking and not being able to find what they were looking for. These two phrases together emphasize that they were trying hard to find help. AT: "We continued looking, but we could not find anyone to help us" (See: [[rc://en/ta/man/translate/figs-metonymy]])
# we watched for a nation that could not rescue us
Here "watched" represents hoping. It can be stated clearly that they were hoping that a nation would come and rescue them. AT: "we hoped for a nation to come and rescue us, but it could not rescue us" (See: [[rc://en/ta/man/translate/figs-metaphor]] and [[rc://en/ta/man/translate/figs-explicit]])