Al-Bait-ul-Ma` mur
وَالْبَيْتِ الْمَعْمُورِ (and by the Populated House [ AI-Bait-ul-Ma` mur ],...52:4) Al-Bait-ul-Ma` mur is the Ka'bah in the heaven meant for the angels' service and is parallel to the Ka'bah on earth. According to a Tradition in Sahihain that the Holy Prophet ﷺ said about his Ascension to the seventh heaven: "Then, I was taken to Al-Bait-ul-Ma` mur. It is visited every day by seventy thousand angels who will not come back to visit it again" because every day other new angels take their turn to visit it. (Ibn Kathir)
Al-Bait-ul-Ma` mur is the Ka'bah of the angels who reside in the seventh heaven. When the Holy Prophet ﷺ reached the seventh heaven on the Night of Ascension, he saw Holy Prophet Ibrahim (علیہ السلام) reclining with his back on Al-Bait-ul-Ma` mur. It was Holy Prophet Ibrahim (علیہ السلام) who built the Ka'bah on earth, and thus the reward is compatible with his action in that Allah Ta’ ala has blessed him with a special connection with Al-Bait-ul-Ma` mur (IbnKathir).