Musannaf Ibn Abi Shayba 3:779

Yahya ibn Adam narrated to us, he said: Yazid ibn Abd al-Aziz narrated to us, from al-A'mash, from Ibrahim al-Taymi, from his father, from Abu Dharr, from the Prophet, peace and blessings of Allah be upon him, who said: "Whoever builds a mosque for Allah, even if it is like the nest of a sandgrouse, Allah will build for him a house in Paradise."