قُلْ يَتَوَفَّاكُمْ مَلَكُ الْمَوْتِ الَّذِي وُكِّلَ بِكُمْ ثُمَّ إِلَى رَبِّكُمْ تُرْجَعُونَ ﴿۱۱﴾ وَلَوْ تَرَى إِذِ الْمُجْرِمُونَ نَاكِسُو رُءُوسِهِمْ عِنْدَ رَبِّهِمْ رَبَّنَا أَبْصَرْنَا وَسَمِعْنَا فَارْجِعْنَا نَعْمَلْ صَالِحًا إِنَّا مُوقِنُونَ ﴿۱۲﴾ وَلَوْ شِئْنَا لَآتَيْنَا كُلَّ نَفْسٍ هُدَاهَا وَلَكِنْ حَقَّ الْقَوْلُ مِنِّي لَأَمْلَأَنَّ جَهَنَّمَ مِنَ الْجِنَّةِ وَالنَّاسِ أَجْمَعِينَ ﴿۱۳﴾

﴾11﴿ Qul yatawaffaakum malakul mawtil lazee wukkila bikum Thumma ilaa rabbikum turja'oon
﴾12﴿ Wa law taraaa izil mujrimoona naakisoo ru'oosihim 'inda rabbihim rabbanaaa absarnaa wa sami'naa farji'naa na'mal saalihan innaa mooqinoon
﴾13﴿ Wa law shi'naa la-aatainaa kulla nafsin hudaahaa wa laakin haqqal qawlu minnee la amla'anna jahannama minal jinnati wannaasi ajma'een

﴾11﴿ Say, The Angel of Death, who has been assigned to you, will take your souls, then you will be returned to your Lord
﴾12﴿ And if you could see when the criminals are made to lower their heads before their Lord, saying, Our Lord, we have seen and heard, so return us [to the world]; we will do righteous deeds. Indeed, we are now certain
﴾13﴿ And if We had willed, We would have given every soul its guidance, but the word from Me has been fulfilled: I will surely fill Hell with jinn and humans all together

[11] This is the response to their denial mentioned in the previous verse.
The essence is that your soul is under the control of Allah, who has appointed the Angel of Death to seize it. It is not beyond the inherent power of the Almighty to bring you back to life.
Note: The objection here is that in this verse, the Angel of Death is mentioned in the singular form, while in Surah Al-An’am (6:61) and Surah Saba (34:11), the plural form (angels) is used. How can this be reconciled?
First answer: The Angel of Death is one, famously known as ʿAzrāʾīl (peace be upon him). (Although to my knowledge, this name is not found in any authentic marfūʿ narration.) However, other angels work under him as assistants. For some souls, he personally comes, and for others, his subordinate angels carry out the task.
Second answer: The narrations cited by commentators about ʿAzrāʾīl (peace be upon him) having full control and knowledge over all souls are not from any authentic marfūʿ sources.
And Allah knows best.
[12] This is a warning of the Hereafter for the deniers, and it describes their condition after the verse "to Him you shall return". By "the criminals" (الْمُجْرِمُونَ) are meant those who deny the Quran, the Messenger, monotheism, and the Resurrection—all of which were mentioned in the preceding verses.
"Their heads are lowered" (نَاكِسُو رُءُوسِهِمْ) signifies the signs of reproach, shame, and humiliation.
"Our Lord, we have seen and heard" (رَبَّنَا أَبْصَرْنَا وَسَمِعْنَا)—the knowledge referred to here is of the very reports they had denied in the world. Most of them rejected things they could not see with their eyes (i.e., those things that are believed in the unseen), and likewise, they did not listen to the revelation of Allah, the Quran, and Hadith in the world. Now, both these states (seeing and hearing) have been forcibly realized for them.
[13] This too is included in the warning, and it is related to "we have seen and heard" (أَبْصَرْنَا وَسَمِعْنَا)—meaning, in the world they did not attain guidance through any means, because guidance is in the control of Allah.
This is the belief of Ahl al-Sunnah: that Allah did not will faith and guidance for the disbeliever, and nothing happens without the will of Allah.