25. And (remember) the Day when the heaven shall be rent asunder with clouds, and the angels will be sent down, with a grand descending. 26. The sovereignty on that Day will be the true (sovereignty) of the Most Gracious, and it will be a hard Day for the disbelievers. 27. And (remember) the Day when the wrongdoer will bite at his hands, he will say: "Oh! Would that I had taken a path with the Messenger.'' 28. "Ah! Woe to me! Would that I had never taken so-and-so as an intimate friend!'' 29. "He indeed led me astray from the Reminder after it had come to me. And Shaytan is to man ever a deserter.''
Here Allah tells us about the terror of the Day of Resurrection and the tremendous events that will happen, including the splitting of heavens when they are pierced by the clouds, that is the shadow of the magnificent light which dazzles all sight. The angels of heaven will come down on that Day and surround all creatures at the place of gathering, then the Lord, may He be blessed and exalted, will come to pass judgement. Mujahid said, "This is as Allah says:
(Do they then wait for anything other than that Allah should come to them in the shadows of the clouds and the angels)'' (2:210)
(The sovereignty on that Day will be the true (sovereignty) of the Most Gracious,) This is like the Ayah,
(Whose is the kingdom this Day: It is Allah's, the One, the Irresistable!) (40:16) In the Sahih it says:
(Allah, may He be exalted, will fold up the heavens in His Right Hand, and will take the earths in His other Hand, then He will say: "I am the Sovereign, I am the Judge. Where are the kings of the earth Where are the tyrants Where are the arrogants'')
(and it will be a hard Day for the disbelievers.) means it will be very difficult, because it will be the Day of justice and the decisive judgement, as Allah says:
(Truly, that Day will be a hard Day -- Far from easy for the disbelievers) (74:9-10). This is how the disbelievers will be on the Day of Resurrection. As for the believers, Allah says:
(The greatest terror will not grieve them.)
(And (remember) the Day when the wrongdoer will bite at his hands, he will say: "O! Would that I had taken a path with the Messenger.'') Here Allah tells us of the regret felt by the wrongdoer who rejected the path of the Messenger and what he brought from Allah of clear truth concerning which there is no doubt, and followed another path. When the Day of Resurrection comes, he will feel regret but his regret will avail him nothing, and he will bite on his hands in sorrow and grief. Whether this Ayah was revealed concerning `Uqbah bin Abi Mu`it or someone else among the doomed, it applies to every wrongdoer, as Allah says:
(On the Day when their faces will be turned over in the Fire) as mentioned in those two Ayat ﴿33:66﴾ Every wrongdoer will feel the ultimate regret on the Day of Resurrection, and will bite at his hands, saying:
(O! Would that I had taken a path with the Messenger. Ah! Woe to me! Would that I had never taken so-and-so as an intimate friend!) meaning, the one among the propagators of misguidance who diverted him from true guidance and led him to follow the path of misguidance, whether this refers to Umayyah bin Khalaf or his brother Ubayy bin Khalaf, or to someone else.
(He indeed led me astray from the Reminder) means the Qur'an,
(after it had come to me.) means, after it had reached me. Allah says:
(And Shaytan is to man ever a deserter (in the hour of need). ) meaning, he leads him away from the truth and diverts him from it, and uses him for the purposes of falsehood and calls him to it.