نَعْبُدُكَ
We worship You.
إِيَّاكَ نَعْبُدُ
You alone we worship.
Both attach worship to the addressee, but the second fronts the object and conveys exclusive devotion more saliently. Its rhetorical emphasis is not identical to placing the object in the ordinary position after the verb.
Fronting and negation–exception can communicate related exclusivity, yet the structures differ in rhythm, informational focus, and the impression they make on the hearer.