Uthman bin Affan, when people criticized him over his rebuilding of the mosque of the Messenger ﷺ, said, "You have said too much. I heard the Prophet ﷺ say, 'Whoever builds a mosque seeking the face of Allah, Allah will build for him one like it in Paradise.'"
أنه سمع عثمان بن عفان يقول عند قول الناس فيه حين بنى مسجد الرسول ﷺ: إنكم أكثرتم، وإني سمعت النبي ﷺ يقول: من بنى مسجدا يبتغي به وجه الله، بنى الله له مثله في الجنة.
Bukhari narrated it in the Book of Prayer (450), and Muslim in the Book of Mosques (533), both of them through the route of Ibn Wahb, who said, "Amr informed me that Bukayr told him that Asim bin Umar bin Qatada told him that he heard Ubaydullah Khawlani," and he mentioned it. The wording given is Bukhari's.