بسم الله الرحمن الرحيم
It is recorded in Hadith and History books that the day on which Makkah was conquered the Holy Prophet Muhammad, may peace and blessings of Allah be upon him, took the keys of Kabah from Hadhrat Uthman Ibn Talha (the key bearer), may Allah be pleased with him, and entered into the Kabah and offered salah. When he came out he called Hadhrat Uthman Ibn Talha, may Allah be pleased with him, and handed the key to him and said:
خذوها يا بنى طلحه خالدة تالدة إلى يوم القيامة لا ينزعها منكم إلا ظالم .
“O people of Banu Talha clan! Take the responsibility of looking after and caring the Holy House of Allah forever till the Day of Judgment, none will take away this key from you but a tyrant.” (Tarikh Makkah Wal Mushrifah Wal Masjid al-Haram Wal Madinah, 63, pub. Beirut, Mojam al-Tabrani al-Awsat, number: 488). From that day onward that clan takes the responsibility even till today.
Allah knows Best!
Darul Uloom Deoband