Hadith: The Prophet Muhammad (sal Allahu alayhi wa salaam) said: "Whoever builds a mosque with the intention of seeking Allah's pleasure, Allah will build for him a place in Paradise." Sahih Al-Bukhai,

Whatever you give or spend in the way of Allah will be returned to you in manifold increase. Allah, the most Bountiful and the most Loving, commends: Lend unto God a goodly loan. Whatever good you shall forward on your behalf you shall find it with God, as better and richer in reward.
[al-Muzzammil
73: 20.]