Tafsir of Muhammad 47:31

His saying, "And We will surely test you," is interpreted in a general sense, meaning: with the command for Jihad and similar burdensome duties, "until We know the mujahideen (those who strive) among you and the patient," those who endure the hardships of these duties. This refers to an actualized knowledge to which recompense is attached. In its meaning is what has been said: that is, "until Our knowledge becomes manifest." Regarding this, Ibn al-Hajib stated: Knowledge is used in the sense of witnessing, and a thing is not witnessed until it occurs—this being the well-known view. It is used here in that sense, or in the sense of recompensing; the meaning being: "until We recompense the mujahideen among you and the patient."

"And We will test your reports," meaning: so that their goodness or badness may become apparent. The statement is a metonymy for testing their deeds, for the goodness or badness of a report depends upon the thing being reported. Thus, when the good report is distinguished from the bad report, the thing being reported—which is the deed—is likewise distinguished. This is more eloquent than saying, "We will test your deeds." The apparent meaning is the generality of the reports. It is also permissible that what is intended by them are their reports regarding their faith and their allegiance to the believers, on the basis that the attribution is to a covenant; that is, "We will test the reports of your faith and your allegiance," so that their truthfulness or falsehood may become manifest.

Abu Bakr recited the three verbs attributed to the pronoun of majesty (the 'We') with a ya (beginning with y-). Ruways recited "wa-nablu" (and We test) with a nun and a quiescent waw, and al-A'mash with a quiescent waw and a ya. Thus, the verb is in the nominative case with a suppressed damma, assuming the implied "wa-nahnu nablu" (and We, We test), and the sentence is a circumstantial clause (haliyya). It is also permissible for it to be in the accusative case, as in the recitation of the majority, where the letter was made quiescent for ease of pronunciation, as in the saying:

God refused that I should be elevated through mother or father.