1. The Sunnah Rakaats of Dhur
The Sunnah Prayers
The Sunnah Rakaats
of Dhur

2. The Sunnah rakaats of Dhur are four, six or eight
Proof of the Four:
Ibn 'Umar said: "We observed and preserved from the Prophet ten rak'at [of sunnah prayers]: two before zuhr and two after it, two after maghrib in his house, two after 'isha in his house and two rak'at before the fajr."
[This is related by al-Bukhari]
Al-Mughirah ibn Sulaiman reports that he heard Ibn 'Umar say: "The Prophet never left the two rak'at before zuhr and two rak'at after it, two rak'at after maghrib, two rak'a~ after 'isha and two rak'at before fajr."
[This is related by Ahmad with a good chain]

3. Proof of the six rakaats of Dhur:
Abdullah ibn Shaqiq said: "I asked 'Aishah about the prayer of the Prophet and she said: 'He would pray four rak'at before zuhr and two after it."'
[This is related by Ahmad, Muslim, and others]
Umm Habibah bint Abu Sufyan reports that the Messenger of Allah said: "Whoever prays twelve rak'at during the day and night will have a house built for him in paradise: four rak'at before zuhr and two after it, two rak'at after maghrib, two rak'at after 'isha, and two rak'at before fajr." This is related by at-Tirmizhi who called it hasan sahih.
[Muslim reports it briefly]

4. Proof of the eight Rakaats of Dhur
Umm Habibah reports that the Prophet said: "Whoever prays four rak'at before zuhr and four after it, Allah will forbid that his flesh be in the fire."
[This is related by Ahmad, Abu Dawud, an-Nasa'i, Ibn Majah, and at-Tirmizhi who calls it sahih]
It is related that Abu Ayyub al-Ansari would pray four rak'at before zuhr. The people said to him: "You made that prayer continue too long!" He said: "I saw the Messenger of Allah doing so. I asked him about it and he said: 'It is a time in which the doors of the heavens are opened and I wish that my good deeds be raised (to heaven) during it.'"
[This is related by Ahmad with a good chain]

5. The virtues of the Four Rakaats before Dhur
Aishah said: "The Prophet never left praying four rak'at before zuhr and two rak'at before fajr under any circumstances."
[This is related by Ahmad and al-Bukhari]
There is no contradiction between the hadith of Ibn 'Umar, which states that the Prophet prayed two rak'at before zuhr, and other hadith which state that the Prophet prayed four rak'at before zuhr. Ibn Hajar writes in Fath al-Bari: "It is better to take them as describing different circumstances, sometimes he prayed two rak'at and sometimes he prayed four rak'at. Some say that it may be construed that if he prayed them in the mos que , he prayed only two rak'at, and when he prayed in his house, he prayed four rak'at. On the other hand, it could imply that he prayed two rak'at in his house and then went to the mosque and prayed two rak'at there also.
Ibn 'Umar only saw what he prayed in the mosque and not what he prayed in his house, while 'Aishah was aware of both of them.
The first interpretation is strengthened by what Ahmad and Abu Dawud recorded from 'Aishah, namely, that the Prophet prayed four rak'at in his house before zuhr and then he went to the mosque."

6. Note the following in regards to praying the sunnah prayers in multiple rakaats:
It is best when praying multiple rakaats of the sunnah prayers to pray them in sets of two's so as to differentiate the sunnah prayers from the obligatory ones.
The Prophet said:
"The prayers of the night and day are (sets of) two [rak'at]."
[This was related by Abu Dawud with a sahih chain]

7. If one is prevented from praying the sunnahs of Dhur he can make them up
Aishah reports that if the Prophet missed the four rak'at before zuhr, he would pray them afterward. [This is related by at-Tirmizhi who calls it hasan ghareeb]
Ibn Majah records that she said: "If the Prophet missed the four rak'at before zuhr, he would pray them following the two rak'at after zuhr."
Concerning making up the two rak'at after zuhr, we have the following reports as recorded by Ahmad.
Umm Salamah says: "The Prophet prayed zuhr and then he received some wealth and he sat to distribute it [and continued to do so] until the mu'azhzhin made the azhan for 'asr. He prayed 'asr and came to me, as it was my day, and he prayed two quick rak'at. I said: 'What are those two rak'at, O Messenger of Allah? Have you been ordered to perform them?' He said: 'No, they are the two rak'at that I perform after zuhr but I was busy distributing this wealth until the azhan was made for 'asr and I hated to miss them.'"
[This is related by al-Bukhari, Muslim, and by Abu Dawud in somewhat different wording]

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