Praying inside the Ka'bah

Question :

Is prayer inside the Ka'bah in any way superior to prayer outside it And is it permissible for a person to speak of what he has seen inside the Ka'bah?

Answer:

Prayer inside the Ka'bah is preferred, if it is possible to do so without any inconvenience, difficulty or harm to anyone, as the Prophet entered it and prayed therein, according to an authentic narration in the Two Sahihs. And it has been reported from him that he came out one day looking sad, and he said:
"Verily, I fear that I may have placed a burden upon my! Ummah (i.e. by entering the Ka'bah)."

And when 'A'ishah, may Allah be pleased with her, asked him about prayer in the Ka'bah, he said:
"Pray in the Hijr, because it is a part of the House.

This proves that prayer inside the Ka'bah is preferred and is a means of drawing close (to Allah) and an act of obedience and in it is great merit.

However, it is not fitting that there should be crowding, or harm, or doing anything which causes difficulty to him or to the people. It is enough for him to pray in the Hijr, because it is a part of the House; and there is no objection to speaking about what he has seen inside the Ka'bah, such as its inscriptions, or what is on its ceiling or the like. There is no objection to a person talking and saying: "I saw such and such and such and such." There is no sin in that.

The Sunnah, when one enters the Ka'bah is to pray two Rak'ahs and to say Allahu Akbar and invoke Allah, the Almighty, the All-powerful with whatever supplications are easy for him at the end of it, especially those which have been reported (from the Prophet) because the Prophet entered the Ka'bah and prayed therein, then he performed Takbir and supplicated Allah. All of this has been authentically reported from him.

Source:
The Permanent Committee
Fatawa Islamiyah, Vol. 2 Pages 255-256