Build Yourself A Palace in Jannah

The five daily Fardh Salahs have stipulated optional [Sunnah] Salahs that accompany each of them.
On the day of Qiyaamah, if there is any deficiency in a person’s Fardh Salah, his Nafl Salah will compensate for that.
(Sunan Tirmidhi, Hadith: 413).

Therefore, utmost care should be taken in correcting and perfecting our Fardh Salah by fulfilling all its requirements as well as by being particular of performing the Sunnah Salah.

Wonderful Reward
Rasulullah (Sallallahu ‘Alayhi Wasallam) said, ‘Whoever performs 12 rak’ahs of Salah in one day excluding the Fardh Salah, he will be granted a house in Jannah.’
(Sahih Muslim, Hadith: 1691)
This Hadith actually inspires the listener into practice.
Therefore, it is no surprise that most of the narrators of the chain of this Hadith in Sahih Muslim have all said:
‘I have not omitted these [12 rak’ahs] since I heard it [from my teacher].’
The 12 rak’ahs have been specifically enumerated in another narration as:

2 rak’ahs before Fajr Salah,

4  rak’ahs before Zuhr Salah,

2  rak’ahs after Zuhr Salah,

2  rak’ahs after Maghrib Salah and,

2  rak’ahs after ‘Isha Salah.

(Sunan Tirmidhi, Hadith: 415).
This Hadith is authentic according to Imam Tirmidhi.

Other specific rewards for each of these salahs.

Before Fajr Salah
The 2 rak’ahs Sunnah before the Fardh of Fajr Salah is the most emphasized Sunnah Salah of the day.
(Sahih Bukhari, Hadith: 1169, Sahih Muslim, Hadith: 1683, Hashiyah Tahtawi pg.212).

Sayyidatuna  Aaishah (Radiyallahu ‘anha) reports that Rasulullah (Sallallahu ‘Alayhi Wasallam) said:
‘The 2 rak’ahs before Fajr Salah are better than the entire world and whatever it contains.
(Sahih Muslim, Hadith: 1685)

Before and After Zuhr Salah
One who offers 4 rak’ahs before Zuhr Salah and follows it up with 4 rak’ahs after the Fardh of Zuhr [2 Sunnahs and 2 Nafl – Fathul Qadir vol. 1 pg. 387], will be protected by Allah from Jahannam.
(Sunan Tirmidhi, Hadith: 427 and Sahih ibn Khuzaymah, Hadith: 1190)

Before ‘Asr Salah
If a person performs 4 rak’ahs before ‘Asr Salah, he will receive a house in Jannah.
(Majma’uz-Zawaid vol. 2 pg. 222)
Rasulullah (Sallallahu ‘Alayhi Wasallam) has made a special du’aa for the mercy of Allah to be showered on such a person.
(Sunan Tirmidhi, Hadith: 430 and Sahih ibn Khuzaymah, Hadith: 1193)

After Maghrib Salah
Makhul (Rahimahullah) reports that Rasulullah (Sallallahu ‘Alayhi Wasallam) said, ‘If the 2 rak’ahs after Maghrib are performed before speaking, it will be lifted high into the heavens.
(Al-Marasil of Imam Abu Dawud, Hadith: 73)

After ‘Isha Salah
Various Sahabah (Radiyallahu ‘anhum) have mentioned that:
If a person performs 4 rak’ahs (2 Sunnah and 2 Nafl) after Isha Salah in the Masjid, he will receive the reward of performing these Salahs on Laylatul Qadr.
(Refer to Musannaf ibn Abi Shaybah, Hadiths: 7347-7353.)

To perform Witr Salah is compulsory in the Hanafi madhab. Rasulullah (Sallallahu ‘Alayhi Wasallam) said, ‘Whosoever does not perform Witr Salah is not among us.’
(Al-Mustadrak vol. 1 pg. 305-306. Imam Hakim has classified this narration as sahih -authentic-. Also refer to Nasbur-Rayah vol. 1 pg. 112.

Bearing in mind the above-mentioned virtues, every Musalli should endeavour to acquire these benefits by remaining steadfast on the Sunnah Salahs, something which people are becoming increasingly lax and unmindful of, these days.
Doing so [i.e. increasing in such optional deeds] will secure one the love and assistance of Almighty Allah.
(Sahih Bukhari, Hadith: 6502)