إِيَّاكَ نَعْبُدُ وَإِيَّاكَ نَسْتَعِينُ
The first three verses speak of God in the third person: "praise is His", "He is al-Raḥmān", "He is the Master of the Day of Judgement." Someone is being described, but He is not in front of us.
In Arabic rhetoric this is called iltifāt — the sudden change of direction in the address. English scarcely uses the device, but its effect is intelligible: it is like speaking about someone and then, in the middle of the sentence, turning to him and beginning to speak to him.
Its function here is very clear. The first three verses are a phase of coming to know: you learn who He is, His relation to you, His mercy, His authority. When the knowing is complete, speaking from a distance ends and one enters the presence. Knowledge turns into relationship.
The structure of the sūra breaks here too: the first half belongs to Him (praise, nurture, mercy, ownership), the second half to the servant (request, path, taking refuge). This verse stands in the middle and binds the two together. The place of which the ḥadīth qudsī says "this is between Me and My servant" is exactly here.
First: "iyyāka" has been brought forward. In Arabic it could have said naʿbuduka (we serve You); it does not, but pulls the object in front of the verb. In Arabic a fronted element conveys restriction — the sense becomes not "we serve You" but "we serve You alone". The sentence is not a report but a choice; it is built by closing every other door.
Second: "iyyāka" is said twice. "Iyyāka naʿbudu wa nastaʿīn" was grammatically possible and shorter. But the word is repeated. Because the two verbs are meant to be assigned separately:
This distinction is very real in practice. A person can direct his worship to God and expect his help from other doors; he can perform his prayers and get his business done through favouritism. The repetition closes this door: both fields are tied to the same place.
The root is ʿ-b-d. The concrete sense is to submit, to yield. But one usage in Arabic lays the spirit of the word bare:
"Ṭarīq muʿabbad" — a road levelled by much walking, its roughness worn away, now easy to pass along.
From the same root. So ʿibāda, within the word's own logic, is: to be levelled by being trodden over and over, to have one's roughness worn away, to become passable. Service here does not mean humiliation but being worked. To pass over the same place again and again — the prayer's being repeated five times a day with the same movements does exactly this work. A road becomes a road by being walked over.
This has several aspects. First, it says that worship is not a private matter but belongs to a community — even alone, a person speaks with the mouth of a congregation. Second, it carries a modest side: a person's own worship may not be worth accepting, but it is being offered from within the community. Third, it prevents the damage "I" would do in this sentence — "You alone I serve" would, while stressing the restriction, unwittingly push the person himself into the foreground.
First what is due is delivered, then a request is made. Before the asking begins, it is established that the relationship is not conditional on the asking — that is, not "I will serve You if You give". Service is unconditional; the request comes after it.
Moreover, asking for help is itself a form of service: it is the admission of one's own incapacity. The two sentences are therefore continuous with each other; they are not two separate acts.