"I prayed two Rak'ah with the Prophet (S) before Az-Zuhr and two Rak'ah after it."  

صَلَّيْتُ مَعَ النَّبِيِّ ﷺ رَكْعَتَيْنِ قَبْلَ الظُّهْرِ وَرَكْعَتَيْنِ بَعْدَهَا قَالَ وَفِي الْبَابِ عَنْ عَلِيٍّ وَعَائِشَةَ  

The Prophet ﷺ never missed four rakʿat before the Zuhr prayer and two rakʿat before the Fajr prayer.  

أَنَّ النَّبِيَّ ﷺ كَانَ لاَ يَدَعُ أَرْبَعًا قَبْلَ الظُّهْرِ وَرَكْعَتَيْنِ قَبْلَ الْغَدَاةِ  

I asked 'A'isha about the Messenger of Allah's ﷺ voluntary prayers, and she replied: Before the noon prayer, he used to pray four rak'ahs in my house; then would go out and lead the people in prayer; then come in and pray two rak'ahs. He would then lead the people in the sunset prayer; then come in and pray two rak'ahs. Then he would lead the people in the 'Isha' prayer, and enter my house and pray two rak'ahs. He would pray nine rak'ahs during the night, including Witr. At night he would pray for a long time standing and for a long time sitting, and when he recited the Holy Qur'an while standing, he would bow and prostrate himself from the standing position, and when he recited while sitting, he would bow and prostrate himself from the sitting position, and when it was dawn he would pray two rak'ahs.  

عَنْ صَلاَةِ رَسُولِ اللَّهِ ﷺ عَنْ تَطَوُّعِهِ فَقَالَتْ كَانَ يُصَلِّي فِي بَيْتِي قَبْلَ الظُّهْرِ أَرْبَعًا ثُمَّ يَخْرُجُ فَيُصَلِّي بِالنَّاسِ ثُمَّ يَدْخُلُ فَيُصَلِّي رَكْعَتَيْنِ وَكَانَ يُصَلِّي بِالنَّاسِ الْمَغْرِبَ ثُمَّ يَدْخُلُ فَيُصَلِّي رَكْعَتَيْنِ وَيُصَلِّي بِالنَّاسِ الْعِشَاءَ وَيَدْخُلُ بَيْتِي فَيُصَلِّي رَكْعَتَيْنِ وَكَانَ يُصَلِّي مِنَ اللَّيْلِ تِسْعَ رَكَعَاتٍ فِيهِنَّ الْوِتْرُ وَكَانَ يُصَلِّي لَيْلاً طَوِيلاً قَائِمًا وَلَيْلاً طَوِيلاً قَاعِدًا وَكَانَ إِذَا قَرَأَ وَهُوَ قَائِمٌ رَكَعَ وَسَجَدَ وَهُوَ قَائِمٌ وَإِذَا قَرَأَ قَاعِدًا رَكَعَ وَسَجَدَ وَهُوَ قَاعِدٌ وَكَانَ إِذَا طَلَعَ الْفَجْرُ صَلَّى رَكْعَتَيْنِ  

The Prophet ﷺ said: If anyone keeps on praying regularly four rak'ahs before and four after the noon prayer, he will not enter the Hell-fire. Abu Dawud said: Al-'Ala' bin Al-Harith and Sulaiman bin Musa reported it from Makhul with his chain, similarly.  

أُمُّ حَبِيبَةَ زَوْجُ النَّبِيِّ ﷺ قَالَ رَسُولُ اللَّهِ ﷺ مَنْ حَافَظَ عَلَى أَرْبَعِ رَكَعَاتٍ قَبْلَ الظُّهْرِ وَأَرْبَعٍ بَعْدَهَا حَرُمَ عَلَى النَّارِ  

"Messenger of Allah would pray four (Rak'ah) after the Zawal of the sun before Az-Zuhr. He said: 'It is an hour in which the gates of the heavens are opened, and I love that a righteous deed should be raised up for me in it.'"  

أَنَّ رَسُولَ اللَّهِ ﷺ كَانَ يُصَلِّي أَرْبَعًا بَعْدَ أَنْ تَزُولَ الشَّمْسُ قَبْلَ الظُّهْرِ وَقَالَ إِنَّهَا سَاعَةٌ تُفْتَحُ فِيهَا أَبْوَابُ السَّمَاءِ وَأُحِبُّ أَنْ يَصْعَدَ لِي فِيهَا عَمَلٌ صَالِحٌ قَالَ وَفِي الْبَابِ عَنْ عَلِيٍّ وَأَبِي أَيُّوبَ  

"When the Prophet (S) would not perform the four Rak'ah before Az-Zuhr he would pray them after it."  

أَنَّ النَّبِيَّ ﷺ كَانَ إِذَا لَمْ يُصَلِّ أَرْبَعًا قَبْلَ الظُّهْرِ صَلاَّهُنَّ بَعْدَهُ