Tafsir of At-Tariq 86:8

The first pronoun refers to the Creator—exalted is His majesty. Just as He glorified [the matter] initially by omitting the agent in His saying, “He was created from a fluid, ejected,”—for the mind does not turn to any creator other than Him, Mighty and Majestic is He—He has likewise glorified it by employing the pronoun in the second instance.

The second pronoun refers to the human being. That is: He who created him initially from what was mentioned is, indeed, capable of restoring him after his death. The expression la-qādir (is indeed capable) signifies "possessing the power." This is similar to the saying:

“If she were to show her upper fangs... she would be poorer than I, for I am poor.”

He intended by it "possessing the poverty and the pain," such that it is valid to present it in opposition to "there is no poverty in me." The emphasis (la-qādir) is to establish the truth of that for which clear evidence has been established in meaning. For this reason, qādir here is interpreted as "possessing power," as stated in al-Kashshāf. He considered it to be specific, saying: "That is, specifically capable of restoring him." It is as if this is because the purpose for which the discourse is driven is precisely that, and everything else is discarded in relation to it. In that case, what was mentioned is intended, making the prepositional phrase (‘alā raj‘ihi) either connected to qādir or indicating its connection to its object, according to the two schools of thought. The sentence is separated from what precedes it because it is the answer to the interrogative, unlike the preceding ones.

Mujahid and ‘Ikrimah said: The second pronoun refers to the fluid. That is: He, the Exalted, is capable of returning the fluid to the urethra or the spine. This is not substantial. The same applies to the interpretation that, assuming it refers to the human being, it means He is capable of returning him from old age to youth, as has been narrated from al-Dahhak. What we mentioned first is that which has been narrated from Ibn ‘Abbas.