。
It is said that the gods strike evil down with lightning.
Literal
Various-gods [topic-は] evil [object-を] lightning [with-で] strike [hearsay-という].
諸神 is a formal/literary compound meaning 'the various gods,' more elevated than 神々. ~という at the end frames the whole statement as hearsay or traditional wisdom — 'it is said that...' — distinct from the verbatim quotation use ~と言う. で here is instrumental ('with lightning') rather than locative. The sentence has a mythological or epigrammatic feel, likely a quoted creed or proverb.