On one occasion, Rasulullah (Sallallahu ‘alaihi wasallam) approached a certain person in Makkah Mukarramah and said to him, “O so-and-so! Why do you not sell your house to me, so that I can use the land to extend the musjid around the Ka’bah, and in reward for this good action (besides the money that you will receive for the house), I will guarantee you a palace in Jannah?” The man replied, “O Rasul of Allah (Sallallahu ‘alaihi wasallam)! By Allah, I do not possess any other house besides this house! If I sell you my house, there will be nothing to shelter my children and I in Makkah Mukarramah.”
Rasulullah (Sallallahu ‘alaihi wasallam) again encouraged the man saying, “Despite what you have mentioned, sell your house to me, so that I can use the land to extend the musjid around the Ka’bah, and in reward for this good action, I will guarantee you a palace in Jannah.” The man replied, “By Allah! I do not intend selling my house.”
Hazrat ‘Uthmaan (radhiyallahu ‘anhu) thereafter learnt of what had transpired. He thus went to the man, who was his friend from the pre-Islamic era, and said, “O so-and-so! I have learned that Rasulullah (Sallallahu ‘alaihi wasallam) intended buying your house, to use the land to extend the musjid around the Ka’bah, and in reward for this good action, he had guaranteed you a palace in Jannah, and you declined to accept his offer.” The man replied, “Yes, I did decline.”
Hazrat ‘Uthmaan (radhiyallahu ‘anhu) then continued to encourage him to sell his house, until he eventually agreed and Hazrat ‘Uthmaan (radhiyallahu ‘anhu) purchased it from him for 10 000 dinars (gold coins).
Hazrat ‘Uthmaan (radhiyallahu ‘anhu) then proceeded to Rasulullah (Sallallahu ‘alaihi wasallam) and said, “O Rasul of Allah (Sallallahu ‘alaihi wasallam)! I learnt that you intended to buy the house of so-and-so, to use the land to extend the musjid around the Ka’bah, and you had guaranteed the owner a palace in Jannah. The house now belongs to me, as I have purchased it from the owner. Will you accept it from me for free and guarantee me a palace in Jannah?” Rasulullah (Sallallahu ‘alaihi wasallam) replied in the affirmative and accepted the house from Hazrat ‘Uthmaan (radhiyallahu ‘anhu), guaranteeing him a palace in Jannah and making the Sahaabah (radhiyallahu ‘anhum) witness to that.
(Fazaa’il-us-Sahaabah lil-Imaam Ahmed bin Hambal #784, Mirqaat 9/3922)