Sahih Muslim | Book 42 | Chapter 4

Narrated by Abdullah al-Khaulani
Abdullah al-Khaulani reported that when Uthman b. 'Affan tried to rebuild the mosque of Allah's Messenger (may peace be upon him) the people began to talk about this. Uthman b. 'Affan said: You discuss it very much whereas I have heard Allah's Messenger (may peace be upon him) as saying: He who builds a mosque and the narrator Bukair said: I think he also said: (for) seeking the pleasure of Allah, Allah would build (a similar house for him in Paradise) and in the narration of Harun (the words are): "A house for him in Paradise.

Narrated by Mahmud b. Labid
Mahmud b. Labid reported that 'Uthman b. 'Affan decided to rebuild the mosque (of Allah's Apostle in Medina) but the people did not like this idea and they wished that it should be preserved in the same (old) form. Thereupon he (Hadrat 'Uthman) said: I heard Allah's Messenger (may peace be upon him) as saying: He who builds a mosque for Allah, Allah would build for him (a house) in Paradise like it.

Narrated by Ja'far
This hadith has been narrated on the authority of Ja'far with the same chain of transmitters with this variation (that the words are): "Allah would build for him a house in Paradise.