The Messenger (sal Allahu alaihi wa sallam) said, “Whoever builds a Masjid for the Sake of Allah, Allah will build for him a house in Paradise.”
[Sahih Al-Bukhari]
Commentary:
The Masajid are the houses of Allah and they are the most honourable places in this world. The Prophet (sal Allahu alaihi wa sallam) showed us that the reward a person receives for building a Masjid for the sake of Allah is that Allah will build for them a house in paradise. The condition of receiving this great reward is sincerity as the Prophet (sal Allahu alaihi wa sallam) mentioned in the hadith “for the sake of Allah” which means that if a person was to build it for other reasons such as reputation or to be praised by people, they are forbidden from this great reward. The hadith also shows the great bounty which Allah has upon His creation whereby He gives such a great reward for this action.
And Allah Knows Best!