... By context we seem to lack an
example where randomness is clearly defined, such as Moses saying to Pharoah,
"Behold, I will now pull A Rabbi out of a Ha", with the Hebrew definite
article used.
Ha! Ha!
Seriously, and if we are talking translation rather than exegesis, it
doesn't work in English to translate "the young woman", or "the virgin".
According to English usage of the article, this would imply a young
woman previously identified in the text, and there is no such young
woman, so the sentence is effectively ungrammatical. In English we have
to say "a young woman", or perhaps "this young woman" referring to only
one present at the time although not previously mentioned - which is a
possible understanding of the Hebrew article.
I say this despite many English translations using "the" here.