The Aa'mal (Deeds) and Fazail (Virtues) Of the Masjid
Allah Subhanahuwa Ta'ala says:
The masjids of Allah are only to be maintained and served by those, who believe in Allah, and the Last Day, and establish Salat, and give Zakat, and fear none save Allah, for (such) it is expected that, they will be of the (rightly) guided. [At-Tawbah 9: 18]
Note: The maintenance of a masjid implies that all the actions of the Masjid of Rasuluilah Sallallahu 'alaihi wasallam are done in it. This includes Da'wat of Iman gatherings in which belief in the unseen is developed, study circles on the virtues of A'mal, acquiring knowledge and Dhikr, the religious education and training of those coming from outside, worship and the services of guests. Another important aspect of the Masjid of Rasulullah Sallallahu 'alaihi wasallam was the sending of the Jama'ats (groups) for Da'wat work, both within the country and to foreign countries. Similarly receiving and being host to Jama'ats from within the country and abroad. This is generally expressed as "Hijrat and Nusrat". (Bayan-ul-Quran)
Describing the condition of the men who have been rightly guided Allah Subhanahu wa Ta'ala says:
In houses (masjids) which Allah has ordered to be raised (to be cleaned, and to be honoured), in them His Name is remembered (i.e. Da'wat, recitation of the Qur'an, learning and teaching the commandments of Allah, worship). Therein glorify Him (Allah) in the mornings and in the evenings. Men whom neither trade nor sale (business) diverts from the Remembrance of Allah (with heart and tongue), nor from establishing Salat, nor from giving Zakat. They fear a Day when hearts will be shaken and eyes will be rolled (out of the horror of the torment of the Day of Resurrection). [An-Nur 24: 36-37]
266. Abu Hurairah Radiyallahu 'anhu narrates that Rasuluilah Sallallahu 'alaihi wasallam said: The parts of the land liked most by Allah are its masjids, and the parts of land disliked most by Allah are its markets. (Muslim)
267. Ibn 'Abbas Radiyallahu 'anhuma narrates that masjids are the houses of Allah on the earth. They shine to the dwellers of the sky, just as the stars shine to the dwellers of the earth. (Tabarani, Majma-'uz-Zawaid)
268. Umar ibn Khattab Radiyallahu 'anhu narrates: I heard Rasullullah Sallallahu 'alaihi wasallam saying: Anyone who builds a masjid where the name of Allah is remembered and (He is praised), Allah will build a palace for him in Paradise. (Ibn Hibban)
269. Abu Hurairah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: Whoever goes to the masjid in the morning or in the evening, Allah prepares for him a good hospitality in Paradise as often as he goes to the masjid, morning or evening (Bukhari)
270. Abu Umamah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: Going to the masjid in the morning or evening is part of Jihad in the path of Allah. (Tabarani, Majma'uz-Zawaid)
271. 'Abdullah Ibn 'Amr ibnil 'As Radiyallahu 'anhuma narrates that Nabi Sallallahu 'alaihi wasallam used to say upon entering the masjid: I seek refuge in Allah the Greatest, and in His Noble Being, and in His Eternal Domain, from the accursed Shaitan. When this Du'a is being recited, Shaitan exclaims: He is protected from me for the rest of the day. (Abu Dawud)
272. Abu Sa'id Khudri Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: Whoever loves the masjid, Allah loves him. (Tabarani, Majma'uz-Zawaid)
273. Abu Darda' Radiyallahu 'anhu narrates: I heard Rasullullah Sallallahu 'alaihi wasallam saying: The masjid is the house of every pious person who fears Allah. For the one who spends most of his time in the masjid, Allah Subhanahu wa Ta'ala has taken upon Himself to comfort him, to bestow Mercy upon him, to make the crossing over Bridge of Sirat easy for him, and to grant him His Pleasure and Paradise. (Tabarani, Bazzar, Majma'uz-Zawaid)
274. Mu'adh Ibn Jabal Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: Verily, Shaitan is the wolf to man, like the wolf that catches sheep; the one which is solitary and the one which stays away from the flock. So avoid staying alone in valleys. Hold firmly to Jamaat (collectiveness), to live with the common people, and to the masjid. (Musnad Ahmad)
275. Abu Sa'id Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said; If you see a man frequenting the masjid, bear witness to his Iman. Allah Subhanahu wa Ta'ala says: Only he will frequent the masjids, who believes in Allah and the Last Day. (Tirmidhi)
276. Abu Hurairah Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: A Muslim that makes the masjid his abode for Salat and Dhikr, Allah is overjoyed with him as a family is overjoyed by the return of an absent relative. (Ibn Majah) Note: Making his abode means that he develops a special attachment to the masjid, and remains there for a major part of his time.
277. Abu Hurairah Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: Whoever has made the masjid his abode, and then was pre-occupied by some matter or illness, and subsequently returned to the masjid as before, Allah is overjoyed with him just as a family is overjoyed by the return of an absent relative, (Ibn Khuzaimah)
278. Abu Hurairah Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: The people who frequent the masjids are (like) their pegs. The angels are their companions. If they are absent the angels search for them, and if they become sick the angels visit them, and if they are in need the angels help them. He (also) said: The one who sits in the masjid, derives at least one benefit from these three: Either he meets a Muslim brother from whom he may benefit in terms of Deen, or he hears a word of wisdom, or receives a Mercy from Allah for which every Muslim waits for. (Musnad Ahmad)
279. 'A'ishah Radiyallahu 'anha narrates that Rasulullah Sallallahu "alaihi wasallam ordered us to build masjids in various localities, and to clean and perfume them. (Abu Dawud)
280. Anas Radiyallahu 'anhu narrates that there was a woman who used to collect rubbish from the masjid. When she died, Nabi Sallallahu 'alaihi wasallam was not informed of her burial. Rasulullah Sallallahu 'alaihi wasallam said: If a person from amongst you dies, then inform me. He then offered Sala-tul-Janazah upon her and said: Verily, I saw her in Paradise because she used to remove rubbish from the masjid. (Tabarani, Majma-'uz-Zawaid)
[Source: Muntakhab Ahadith]