الطَّالِبُ مُجْتَهِدٌ.
The student is diligent.
A nominal clause can present diligence as a stable characteristic. Yajtahidu al-ṭālib may foreground the occurrence or recurrence of effort, although the precise contrast is contextual.
A nominal clause does not entail eternal permanence; a verbal one does not necessarily imply a single isolated event. Rhetorical tendency should not be turned into an absolute temporal rule.