ٱلَّذِى خَلَقَ فَسَوَّىٰ
The second, third and fourth verses begin with ٱلَّذِى. The three verses, that is, are attributes of the word rabbika in the first verse.
This is a method of introduction: a command is given, and then the one to whom the command is directed is introduced by the works He has done. We had seen the same structure in Sūrat al-ʿAlaq: iqraʾ bi-smi rabbika'lladhī khalaq — there too alladhī came immediately after the command, and the first work was again creating.
Note: in the second verse there is no conjunction (alladhī khalaqa); in the third and the fourth there is (wa'lladhī). The first attribute is directly attached to what it qualifies; those that follow are added to it. This is the same phenomenon as the one recorded at al-Ikhlāṣ 112/2: the dropping of the conjunction shows that the first quality is inseparable from what it qualifies.
This was so at al-ʿAlaq 96/1 as well, and there the function of dropping the object was recorded: generality. When the object is not stated the verb stays open so as to cover every object that fits the subject.
Here this has a consequence: the following verses will give examples one by one (the pasture, the animal, the human being), but the first sentence stays without limit. First the scope is opened, then examples are placed inside it.
Root: س-و-ي. This root was taken up in the section on Sūrat al-Shams (wa nafsin wa mā sawwāhā). What was recorded there:
The idea beneath the root is equality and equivalence. In Form II (sawwā) the verb becomes transitive and intensive: to bring the parts of a thing into correspondence with one another, to get their proportions right, to make it complete and without flaw. To render it "to straighten" in English falls short; the work described is putting the parts of a thing into their right proportion — like bringing the walls of a building to the plumb line, or balancing the pans of a scale.
In the section on al-Shams the verses in which this verb occurs were listed, and al-Aʿlā 87/2 was on that list too. Let us now look at the list from here:
In all these verses there was a common order: first creating, then proportioning, then the giving of a capacity. al-Aʿlā 2-3 sets up the same order but names the third step differently: hadā.
In the section on Sūrat al-Ḍuḥā the function of this particle was recorded: taʿqīb (following immediately) and causation. There it was repeated in three verses: fa-āwā, fa-hadā, fa-aghnā.
In al-Aʿlā the same particle is repeated three times: fa-sawwā, fa-hadā, fa-jaʿalahu. And there is one verb common to the two sūras: fa-hadā.
The pattern set up in al-Ḍuḥā was this: a state of lack → a direct answer to it. In al-Aʿlā the pattern is different: a work → the completion of that work. In al-Ḍuḥā a deprivation is removed; in al-Aʿlā a process of making comes to its result.
The meaning of the particle here is this: there is no gap between creating and proportioning. What is created has not been left raw and put right afterwards; being created and being brought to its proportion are two moments of the same operation.