From my old A Picture Book of Idioms in Five Languages (1993):
He/she doesn’t snatch stars from the sky. – Russian version (in English translation) He didn’t invent powder. – French, Spanish, Russian,… He is not a great torch-bearer. – German
He won’t set the Thames on fire. - English
This English saying is obviously rises curiosity – why do you say it so – referring to the impossible event?
(Or maybe, ‘set on fire’ is used here in some indirect sense – in particularly, I saw old English pictures with great national celebrations (or grief for actually great persons, like Lord Nelson…) and the Thames on them can actually be viewed as being ‘on fire’.
We don’t have the Thames here in America, and we don’t think about it much. We say instead, He won’t set the world on fire. You can replace the world with other things, such as the engineering profession, his field, etc.
By the way, it’s not impossible for a river to catch fire. In the 1970s, both the Cuyahoga River in Ohio, and the Rouge River in Michigan, became so polluted that they actually caught fire. Now they have been cleaned up, and people can actually fish in them.
In Russian we also use it for the hand of God (= божья воля)
Not with the ordinal finger, but only and always with the very old word for ‘finger’ - перст. (By the way, the word ‘перстень’ - finger ring - is still in use.)
But generally ‘перст божий’ (finger of God) sounds very… churchly and in colloquial speech it is always used a bit ironically.
Coming back to the (another) saying God’s spark – if you say something like ‘Certainly, God had kissed him at his birth’ then an average Russian more likely understands it as ‘he is actually gifted/talented, there is the God’s spark inside him’.
But some people might also take it as an equivalent for the idiom ‘be born under a lucky star’, be born with a silver spoon in one’s mouth’, etc.
Briefly - for jammy = lucky (British slang )