I used to wish that I could enter the House and pray inside it. So the Messenger of Allah ﷺ took me by the hand and brought me into the Hijr and said, "When you want to enter the House, pray here, for it is a portion of the House. Your people simply fell short when they rebuilt it."
أخبرنا إسحق بن إبراهيم قال أنبأنا عبد العزيز بن محمد قال حدثني علقمة بن أبي علقمة عن أمه
كنت أحب أن أدخل البيت فأصلي فيه فأخذ رسول الله ﷺ بيدي فأدخلني الحجر فقال إذا أردت دخول البيت فصلي ها هنا فإنما هو قطعة من البيت ولكن قومك اقتصروا حيث بنوه
Its isnad is sahih. Abu Dawud narrated it in Manasik, chapter on prayer in the Hijr, no. 2028, and Tirmidhi in Hajj, chapter on what has been said about prayer in the Hijr, no. 876, from the hadith of Abdul-Aziz Darawardi through this route, and Tirmidhi said, "Hasan sahih." It is also in Kubra, no. 3895.