Tajdeed

اللَّهُ يَتَوَفَّى الْأَنفُسَ حِينَ مَوْتِهَا وَالَّتِي لَمْ تَمُتْ فِي مَنَامِهَا ۖ فَيُمْسِكُ الَّتِي قَضَىٰ عَلَيْهَا الْمَوْتَ وَيُرْسِلُ الْأُخْرَىٰ إِلَىٰ أَجَلٍ مُّسَمًّى ۚ إِنَّ فِي ذَٰلِكَ لَآيَاتٍ لِّقَوْمٍ يَتَفَكَّرُونَ
Sahih International
Allah takes the souls at the time of their death, and those that do not die [He takes] during their sleep. Then He keeps those for which He has decreed death and releases the others for a specified term. Indeed in that are signs for a people who give thought. (39:42)

This verse is profound regarding the topic of Ajal because the verse differentiates between the Ajal Mu’allaq (Flexible time of death) and the Ajal Musamma (Specified, fixed, named time of death) if one contemplates on the verses properly. Once the seeker of truth compares the different passages of the Qur’an about the same subject matter, then they will reach the correct understanding, God-willing.

هُوَ الَّذِي خَلَقَكُم مِّن طِينٍ ثُمَّ قَضَىٰ أَجَلًا ۖ وَأَجَلٌ مُّسَمًّى عِندَهُ ۖ ثُمَّ أَنتُمْ تَمْتَرُونَ
Sahih International
It is He who created you from clay and then decreed a term and a specified time [known] to Him; then [still] you are in dispute. (6:2)

Before beginning the tafsir of this verse, it is established that the word Ajal refers to any term or time of death. Therefore, the word ‘Ajal’ alone is not a specific time of death, rather it is general and it is synonymous to the ‘time of death’.

Clarifying this key detail, the first described group who have their souls taken during their sleep via Qadha meet their Ajal (the conditional Ajal) and the reason for this is because in contrast to those who are decreed to die, the people who have their life extended until their Ajal Musamma are able to actually reach the Ajal Musamma, which is the actual point a person is supposed to live up until.

We understand that the Ajal Musamma is the potential that the life form can live up to and the other forms of Ajal which are conditional and flexible are the times of death that are different from the actual time of death (Ajal Musamma), which is when death is decreed for the person before they reach their specified term (Ajal Musamma).

The actual age the body will continue living until is the original or actual time of death (Ajal Musamma). However, at times Allah decrees to bring the time of death or Ajal closer than the actual Ajal Musamma because of what they have earned with their own hands. As a result of their actions, Allah decrees (Qadha) to take their lives during sleep before they reach the originally actual appointed term (Ajal Musamma). 

We have understood this implicit distinction from the wording  فَيُمْسِكُ الَّتِي قَضَىٰ عَلَيْهَا الْمَوْتَ which translates into, ‘he takes those whom he decreed death’. It is understood that although the word Ajal is not used for this Divine action of taking the lives of those in their sleep, the truth is that this is also an Ajal because every time of death is an Ajal. 

The important part is that the latter part of the verse clarifies that others have been given a respite until their Ajal Musamma which means that there are two Ajals, one changeable and the other one specified. Some people meet their Ajal earlier due to God decreeing to take their souls during their sleep, whereas others have been given respite til they reach their innate actual age of death which is called the specified term of death. 

يَغْفِرْ لَكُم مِّن ذُنُوبِكُمْ وَيُؤَخِّرْكُمْ إِلَىٰ أَجَلٍ مُّسَمًّى

“He will forgive you of your sins and grant you respite for an appointed term.” (71:4)

The reason why God says He will forgive your sins and give you respite in this verse is because the severity of the sins committed by the people could have changed their time of death, and bring their Ajal closer before they were able to reach their actual Ajal Musamma. However, amending their ways and repenting back to God allowed the early Divine punishment of death from befalling them and instead God planned or decreed to extend their life back to the original time of death (Ajal Musamma).

وَمَا تَفَرَّقُوا إِلَّا مِن بَعْدِ مَا جَاءَهُمُ الْعِلْمُ بَغْيًا بَيْنَهُمْ ۚ وَلَوْلَا كَلِمَةٌ سَبَقَتْ مِن رَّبِّكَ إِلَىٰ أَجَلٍ مُّسَمًّى لَّقُضِيَ بَيْنَهُمْ ۚ وَإِنَّ الَّذِينَ أُورِثُوا الْكِتَابَ مِن بَعْدِهِمْ لَفِي شَكٍّ مِّنْهُ مُرِيبٍ

Sahih InternationalAnd they did not become divided until after knowledge had come to them – out of jealous animosity between themselves. And if not for a word that preceded from your Lord [postponing the penalty] until a specified time, it would have been concluded between them. And indeed, those who were granted inheritance of the Scripture after them are, concerning it, in disquieting doubt. (Surah 42:14)

From Abul Hasan al-Shaddadi