Commentary
And when the Exalted informed about the emergence of the burdens from which the dead arise, the longing intensified for the state of that emergence and what would result from it. He said, repeating the mention of the Day as an increase in the terror: "On that Day" meaning at the time that has preceded, which is when the people rise from their graves. "They will return" meaning they will return in a manner that is extremely swift and guided to the place from which they will be called, no one among them will err in it nor go astray. "The people" from their graves to their Lord who has been waiting for them to separate between them. "In groups" meaning they will be scattered according to their ranks in essence and conditions, from believer and disbeliever, secure and fearful, obedient and disobedient.
And when he mentioned that, he followed it with its reason, saying in a manner befitting the speech of the able: "So that they may see" meaning Allah sees the good-doer among them and the wrongdoer through whom He wills from His soldiers or without an intermediary when He speaks, glorified and exalted is He, to each one without a translator or intermediary, as His Messenger has informed about that. "Their deeds" so that they may know their recompense or departing from the position, each one to his abode to see the recompense of his deeds. Then he caused this to follow with his statement, detailing the sentence that preceded it:
Explore Other Scholars on This Verse
Compare different scholarly perspectives on Surah Az-Zalzalah verse 6