What is the virtue of one who spends from his private money on the upkeep of a mosque among the mosques of Allah?

The construction, restoration, and maintenance of mosques are all part of the 'amarat al-masajid (beautification/upkeep of mosques), which Allah praised those who undertake it, saying: "The mosques of Allah are only to be maintained by those who believe in Allah and the Last Day and establish prayer and give zakah and do not fear except Allah. For it is expected that those will be of the guided." (Quran 9:18). This also falls under the category of perpetual charity (sadaqah (definition) jariyah). On the authority of Abu Hurayrah, may Allah be pleased with him, he said: The Messenger of Allah, peace and blessings be upon him, said: "Indeed, among the good deeds and merits that follow a believer after his death are... and a mosque he built." Regarding the virtue of spending on mosques, it was narrated from the Prophet, peace and blessings be upon him: "Whoever builds a mosque for Allah, even like a bird's nest or smaller, Allah will build for him a house in Paradise." Scholars have interpreted this as an exaggeration, or referring to an addition to an existing mosque, or the participation of a group in its construction. It is also narrated in the Sahihayn: "Whoever builds a mosque, seeking thereby the Face of Allah, Allah will build for him a similar house in Paradise." The similitude here may refer to the naming of the house with its excellent description, or to the superiority of the mosque over the houses of this world.