نَعْبُدُكَ
We worship You.
إِيَّاكَ نَعْبُدُ
You alone we worship.
In the first sentence the object follows the verb, and the clause states the act of worship in relation to the addressee. In the second, the object is fronted, giving special restrictive emphasis.
This does not license a universal claim that every fronted object always carries full exclusivity. Here the religious context and the rejection of alternative objects of worship make the restriction salient.