Hadith: 'A'ishah Radiyallahu 'anha narrates that Nabi Sallallahu 'alaihi wasallam said: He who is regular in offering twelve Rak'at (of Salat), Allah Subhanahu wa Ta'ala will build for him a house in Paradise; four Rak'at before Zuhr, two Rak'at after Zuhr, two Rak'at after Maghrib, two Rak'at after 'Isha, and two Rak'at before Fajr. (Nasai: 1796)
Hadith: Abu Umamah Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: Allah does not grant a slave to engage in anything more rewarding for him than two Rak'at, which he offers, Verily righteousness is spread over his head so long as he is engaged in Salat. And man does not come nearer to Allah with anything better than that which came forth from Allah 'Azza wa Jall, meaning thereby the Qur'an. (Tirmidhi: 2911)
Note: Apart from the importance of Nafl Salat, this hadith explains that the maximum closeness to Allah Subhanahu wa Ta'ala is achieved by reciting of the Qur'an.
Hadith: Abu Hurairah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: I thought of asking some youngsters to collect a large quantity of firewood, and then proceed to the houses of those people who offer their obligatory Salat in their homes without any valid excuse, and burn their houses on them. (Abu Dawud: 549)
Hadith: Abu Hurairah Radiyallahu 'anhu narrates that Rasullullah Sallallahu 'alaihi wasallam said: If people would have known the virtues of going to the masjid for Zuhr Salat in the scorching heat, then they would certainly compete with one another in going to the masjid. And if they knew the virtues of 'Isha and Fajr Salat, they would indeed go to the masjid for these Salat, even if (due to some illness) they had to drag themselves. (Bukhari: 615)
Hadith: Fadalah Ibn 'Ubaid Radiyallahu 'anhu narrates that when Rasullullah Sallallahu 'alaihi wasallam used to lead the Salat, some people standing in the row would fall down due to extreme hunger; and they were the people of Suffah about whom the villagers would say that they were insane. One day, when Rasullullah Sallallahu 'alaihi wasallam completed the Salat, he turned to them and said: If you know the reward that Allah has for you, then you would like to live with more hunger and needs. Fadalah says: I was with Rasullullah Sallallahu 'alaihi wasallam that day. (Tirmidhi: 2368)
Hadith: Anas Radiyallahu 'anhu narrates that Nabi Sallallahu 'alaihi wasallam said: Straighten your Rows, for straightening of the rows in Salat is essential for the offering of Salat correctly. (Bukhari: 723)
Hadith: 'A'ishah Radiyallahu 'anha narrates that when Nabi Sallallahu 'alaihi wasallam fell ill, he asked for permission from his wives that his nursing be done in my house. They gave him their consent. When Rasullullah Sallallahu 'alaihi wasallam came out (for Salat) with the support of two persons, his feet were making a line on the ground (as a result of trailing along). (Bukhari: 198)
