Sayyiduna Usamah (may Allah be pleased with him) said: The Messenger of Allah (peace and blessings be upon him) said to the owner of the plot of land that was added to the Mosque of Madinah - and its owner was a man from the Ansar - the Prophet (peace and blessings be upon him) said to him: "For it you will have a house in Paradise." The narrator said: Then Sayyiduna Uthman (may Allah be pleased with him) came and said to him: "You will get ten thousand (dirhams) for it," and so he bought the land from him. Then Sayyiduna Uthman (may Allah be pleased with him) came to the Prophet (peace and blessings be upon him) and said: "O Messenger of Allah! Buy from me the plot that I bought from the Ansari." So he bought the land from him in exchange for a house in Paradise. Sayyiduna Uthman (may Allah be pleased with him) said: "I bought this land for ten thousand dirhams." Then the Prophet (peace and blessings be upon him) laid a brick, then he called Sayyiduna Abu Bakr (may Allah be pleased with him) and he laid a brick, then he called Sayyiduna Umar (may Allah be pleased with him) and he laid a brick, then Sayyiduna Uthman (may Allah be pleased with him) came and he laid a brick. Then he (peace and blessings be upon him) said to the people: "You lay (bricks) too," so they (also) laid bricks.
Hadith Referenceالمعجم الكبير للطبراني / باب الألف / 518