The verse 187 speaks of the third principle, that is, the life in the Hereafter (آخرَت). The revelation of this verse is related with the following incident reported by Ibn Jarir and ` Abd ibn Humaid on the authority of Qatadah.
The Quraish of Makkah once asked the Holy Prophet ﷺ by way of mockery as to when the Hour of doom was to occur of which he used to warn them so often. The verse was revealed in response to this question.
The Arabic word Sa` ah سَاعَۃ signifies a short period without specific number of minutes or hours, while in our calendar it is a single unit out of twenty four units of the day and night. In Qur'anic terminology, however, it is used for the day when all the created beings will cease to exist, as well as for the day when all the creation shall be revived and presented before the Lord of all the creations. مُرسٰی Mursa signifies to stop or to stay, لَا يُجَلِّيهَا ' is a derivative of تَجلِیہ which means to disclose or open. Baghtatan بَغتۃ means suddenly while the word 'Hafiyyun' حَفِیُّ is used for a scholar or a knowledgeable person according to Sayyidna ` Abdullah Ibn ` Abbas ؓ The word is generally used for a person who invests his effort and employs all his resources to ascertain some-thing.
The quintessence of the verse, therefore, is that the Quraish of Makkah should be answered that the exact time of the Doom is not known, and shall never be made known to anyone. It is a divine secret which shall disclose itself by it's sudden occurrence, as has been decided by the Qur'anic phrase "It shall not come upon you but suddenly".
Al-Bukhari and the Muslim have reported on the authority of Sayyidna Abu Hurairah ؓ that the Holy Prophet ﷺ said with regard to sudden occurrence of the 'Qiyamah' (The Doomsday) that it has been made a close secret. The wisdom behind it is obviously to make people live their lives peacefully which would have not been possible in case the definite time of death was known to them. Besides, those who do not believe in Doomsday would have made mockery of it by knowing the remotely long period of its occurrence. The divine wisdom chose to keep it undefined in order to keep people vaguely in fear of its dreadful events which, in fact, is an effective measure against crime and corrupt practices.
By implication, the above verses make us alive to the fact that once we have come to believe that the day of Qiyamah has inevitably to come and all the created beings shall necessarily be presented before the Lord of all the creation and be called to account for all their minor or major deeds, and shall be rewarded or punished according to their performance in this world, the knowledge of time and period of the death becomes immaterial. It will not be wise to waste precious time of one's life in futile discussions like the time of occurrence of the Doomsday. On the contrary, human reason and wisdom demands that every moment of uncertain period of life is spent carefully in preparing oneself for the great Day of Judgment. This answer to the Quraish of Makkah made it clear that their question regarding the time of the Doomsday was a product of their ignorance. The next phrase of this verse speaks of another misconception of the disbelievers of Makkah. It said:
يَسْأَلُونَكَ كَأَنَّكَ حَفِيٌّ عَنْهَا
"They ask you as if you were aware of it."
They thought that the Holy Prophet had, somehow, secured the knowledge of the exact time of the occurrence of the Doomsday and that he was not disclosing it for some purpose. They
insisted him to disclose it to them. The Holy Prophet ﷺ was
asked to answer them in these words:
قُلْ إِنَّمَا عِلْمُهَا عِندَ اللَّـهِ وَلَـٰكِنَّ أَكْثَرَ النَّاسِ لَا يَعْلَمُونَ
"Say, it's knowledge is only with Allah, but most of the people
do not know."
That is, it is not necessary for a prophet to know the definite time of the Doomsday or certain other matters that are kept secret by Allah. The lack of knowledge in such matters on the part of a prophet cannot, therefore, be taken as a proof against his prophethood. (The knowledge of a prophet can never be equal to the All-encompassing knowledge of Allah.)
The Holy Prophet ﷺ ، however, was given knowledge of certain specific signs indicating that the Doomsday was in proximity. He has informed the Muslim Ummah of all these signs in explicit terms in his Traditions. In one of such Traditions he said that his appearance and the Day of Qiyamah were as close to each other as two fingers of a hand. (Tirmidhi)
As for the reports giving the total age of this world as seven thousand years, they are the reports borrowed from some Israelite literature in certain Islamic books. They are neither authentic nor do they have any basis in the Qur'an and the Sunnah. Similarly, geo-physical data of modern knowledge giving the age of this world as millions of years do not confront or contradict any of the Qur'anic verse or any authentic Tradition of the Holy Prophet ﷺ . On the contrary, the Holy Prophet ﷺ addressing the Muslim Ummah said in a Tradition:
"When compared to the early people, you are like a white thread of hair on the body of a black ox."
This gives us an idea of the enormous age of this world as thought by the Holy Prophet ﷺ . Hafiz Ibn Hazm of Spain has, therefore, concluded that the exact age of this world cannot be assessed by any one1. (Marghni)
1. By inference it seems physically impossible to have an exact assessment of the age of this universe, because it would give the exact time of the end of this universe which has been precluded by the above verse saying that the knowledge of the occurrence of the Doomsday is not known to any one but Allah. (Translator)