Hadith: The keys of the unseen are five

عَنْ ابْنِ عُمَرَ رَضِيَ اللَّهُ عَنْهُما أَنَّ رَسُولَ اللَّهِ صَلَّى اللهُ عَلَيْهِ وَسَلَّمَ قَالَ:
«مَفَاتِحُ الغَيْبِ خَمْسٌ، {إِنَّ اللَّهَ عِنْدَهُ عِلْمُ السَّاعَةِ وَيُنْزِلُ الغَيْثَ وَيَعْلَمُ مَا فِي الأَرْحَامِ وَمَا تَدْرِي نَفْسٌ مَاذَا تَكْسِبُ غَدًا وَمَا تَدْرِي نَفْسٌ بِأَيِّ أَرْضٍ تَمُوتُ إِنَّ اللَّهَ عَلِيمٌ خَبِيرٌ}».
[صحيح] - [رواه البخاري] - [صحيح البخاري: 4627]

Ibn ‘Umar (may Allah be pleased with him and his father) reported that the Messenger of Allah (ﷺ) said:
"The keys of the unseen are five {Indeed, Allah has the knowledge of the Hour. He sends down the rain and knows what is in the wombs. No soul knows what it will do tomorrow, nor does any soul know in which land it will die. Indeed, Allah is All-Knowing, All-Aware.}"
[Authentic hadith] - [Narrated by Bukhari] - [Sahih Bukhari - 4627]

Explanation

The unseen belongs to Allah alone; none knows it except Him. The Prophet (ﷺ) informed us that the keys and treasures of the unseen are five: First: None knows when the Hour will occur except Allah—this refers to the knowledge of the Hereafter, for the Day of Judgment is its beginning. And if the knowledge of its beginning is unknown, then all that follows it is even more hidden. Second: None knows when rain will come except Allah—this refers to matters of the higher world. Rain is mentioned specifically, even though there are apparent causes that may indicate its coming by custom and observation, yet these causes do not provide certainty or exact knowledge. Third: What is in the wombs—whether male or female, black or white, complete or defective, wretched or blessed, and the like. The womb was mentioned specifically because people often make assumptions about it based on customary signs, yet Allah denied that anyone truly knows its reality; and if this is the case for what is most observable, then what is beyond it is even more hidden and unknowable. Fourth: No one knows what will happen tomorrow except Allah—this refers to the events that occur within time and its unfolding happenings. The word “tomorrow” is mentioned specifically because it is the nearest of future times; so if no one truly knows what will occur in such a near time—despite possible signs or indications—then knowledge of what lies further ahead is even more beyond reach. Fifth: No soul knows in what land it will die—this refers to matters of the lower world. Although people generally die in their homelands, this is not always the case. Even if one dies in their own land, they do not know the exact spot where they will be buried, even if there is a graveyard of their ancestors. {Indeed, Allah is All-Knowing, All-Aware}—He encompasses all things, outward and inward, the hidden and the unseen, the secrets and the mysteries. Thus, this verse includes all types of the unseen and refutes every false claim to the knowledge of it.

Benefits from the Hadith

1. A clarification of the five treasures of the unseen, which none knows except Allah.
2. As-Sindi said: His statement (the keys of the unseen are five)— these five are called the keys of the unseen because whoever possesses knowledge of these five, possesses knowledge of all the unseen. Thus, they are like the means by which the treasures of the unseen are unlocked.
3. Ibn Hajar said: Ibn Abi Jamrah said: The term "keys" was used to make the meaning easier for the listener to grasp. Everything that is veiled from you is considered unseen to you, and access to what is behind a veil or barrier is usually through a door. When the door is locked, one needs a key to open it. So, if a person cannot even know where the key to what is hidden is kept, then how could he possibly know the unseen itself?
4. Ibn Abi Jamrah said: The wisdom behind making them five is to indicate that all realms of existence are encompassed within them.
5. Allah Almighty may reveal some aspects of the unseen to His messengers, out of His divine wisdom.
6. The false claims of astrologers and soothsayers regarding their knowledge of the unseen are invalidated, for whoever claims to know anything of the unseen that Allah Almighty alone possesses has indeed belied Allah Almighty, His Messenger (ﷺ), and the Noble Qur’an.