Kaaba Door: This is the entrance to the Kaaba from the east. It was originally at ground level, but was raised when the Quraysh restored the Kaaba.
When Ibrahim (peace be upon him) built the Kaaba, the openings of the Kaaba were at ground level. People entered from the east opening and left through the west opening.
Aisha (may Allah be pleased with her) once asked the Prophet (saw) why the Quraysh had raised the door above the ground. The Prophet (saw) answered: “Your people made it so that they could let into the Kaaba only those people whom they approved and could interfere with those whom they wanted. If your people were not recently removed from ignorance, and if I were not afraid that they would not want to change, I would have turned Hatim into the Kaaba and raised the door to ground level.
At the top of each door is written: “Allah Jal Jalal Muhammad sallalla’ahu alai’hi wa’sallam.”
Under all of this is written: “In the name of Allah, the Most Gracious, the Most Merciful. “(It will be said to them): ‘Enter therein (Paradise), in peace and security. [Quran 15-Sura Hijr, verse 46]
Allah has made the Ka’bah, the Sacred House, an asylum of security and Hajj and ‘Umrah (pilgrimage) for mankind, and also the Sacred Month and the animals of offerings and the garlanded (people or animals, etc. marked with the garlands on their necks made from the outer part of the stem of the Makkah trees for their security), that you may know that Allâh has knowledge of all that is in the heavens and all that is in the earth, and that Allâh is the AllKnower of each and everything. ” [Quran 5- Al-Maeda, verse 97]
Say: “Oh, my Rabb! Let me go to a pleasant place, let me go nicely and give me such authority from Myself that in combination with (your) help. ” [Quran 17- Al-Isra, verse 80]
“Your Rabb made mercy (to you) obligatory for you.” [Al-Anaam, verse 5]
Your rabb says: “Supplicate to Me and I will answer.” [Al-Muamin, verse 60]
Under all this it is written: “Oh, my servants, who offended their souls (having committed kufr or other sins)! Never lose hope in the mercy of Allah. ” [Al-Zumar, verse 53]
The words “Allahu Akbar” are inscribed on two rings, and Sura Fatiha is engraved beneath the lock.
Source: The History of Makkah Mukarramah – Dr. Muhammad Ilyas Abdul Ghani