Tafsir of Al-Lail 92:12

This is a new commencement, confirming what preceded it. It means: "Upon Us, by virtue of Our decree—which is established upon profound wisdom in that We created creation for worship—it is incumbent to guide them and direct them to the truth, or to clarify to them the path of guidance and what leads to it, and the path of misguidance and what leads to it." We have already performed this in such a way that there is no room for dispute regarding it. Thus, the verse does not constitute a valid argument for an obligation upon Him—Mighty and Majestic is He—in the sense claimed by the Mu‘tazila.

It has been said that the meaning is that guidance is entrusted to Us, not to anyone else, just as He—the Glorified—said: "Indeed, you do not guide whom you like, but Allah guides whom He wills." The meaning is not that guidance is incumbent upon Us such that its apparent phrasing would serve as evidence for the obligation of "what is most beneficial" (al-aslah) upon the Exalted—He is far above that with a great exaltation.

As for the view that the prepositional phrase relates to a specific verb, meaning "entrusted," this is contrary to the apparent meaning. Similar to this is the claim that the meaning is "Upon Us is the way of guidance," in the sense that whoever traverses the way made clear by guidance and instruction reaches Us. This is as was said regarding the saying of the Almighty: "And upon Allah is the [responsibility of] the straight path," meaning: whoever traverses the straight path, which is the upright one, reaches Him—the Glorified.