´Aisha said:` "I said: 'O Messenger of Allah! Can I not enter the House?' He said: 'Enter the Hijr for it is part of the House.'"
Explanation & Benefits
Hafiz Muhammad Ameen
Although the "Hijr" is (an internal) part of the Ka'bah, one should not perform prayer facing only towards the Hijr, because according to some narrations, a portion of external space is also included in it. Therefore, the Ka'bah itself should also be in front (as the direction of prayer).
Source: Sunan Nasa'i: Translation and Benefits by Shaykh Hafiz Muhammad Amin Hafizullah, Page: 2914