مُسْنَدُ أَحْمَدَ
Musnad Ahmad 2153
Musnad of 'Abdullah bin al-'Abbas bin 'Abdul-Muttalib from the Prophet
It was narrated from Ibn 'Abbas (رضي الله عنه), from the Prophet (ﷺ), that he said: "Whoever builds a mosque for Allah, even if it is like a sparrow's nest for its egg, Allah will build for him a house in Paradise.”
Musnad Ahmad 2157Saheeh because of corroborating evidence; this is a da’eef i