Syntax asks how conditional particles govern verbal forms, how idha functions adverbially, and where the conditional response belongs. Rhetoric asks why the speaker chose to frame the event as open rather than expected.
إِنْ يَجْتَهِدِ الطَّالِبُ يَنْجَحْ
If the student works hard, he will succeed.
The jussive endings belong to grammatical government. The noncommittal presentation of whether he will work hard is a semantic or rhetorical matter. Grammar and rhetoric analyze different layers of the same utterance.