"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