"Messenger of Allah (S) would pray four Rak'ah before Al-Asr separating between them with At-Taslim upon the angels that are close (to Allah) and those who follow them among the Muslims and the believers."  

كَانَ النَّبِيُّ ﷺ يُصَلِّي قَبْلَ الْعَصْرِ أَرْبَعَ رَكَعَاتٍ يَفْصِلُ بَيْنَهُنَّ بِالتَّسْلِيمِ عَلَى الْمَلاَئِكَةِ الْمُقَرَّبِينَ وَمَنْ تَبِعَهُمْ مِنَ الْمُسْلِمِينَ وَالْمُؤْمِنِينَ  

"We asked 'Ali about the prayer of the Messenger of Allah ﷺ. He said: 'Who among you could manage to do that?' We said: 'Even if we cannot do it, we still want to hear about it.' He said: 'When the sun reached the same height (in the east) as it reaches (in the west) at the time of 'Asr, he would pray two rak'ahs, and when the sun reached the same height (in the east) as it reaches (in the west) at the time for Zuhr he would pray four Rak'ahs. He would pray four Rak'ahs before Zuhr and two after, and he would pray four Rak'ahs before 'Asr, separating each two Rak'ahs with Taslim upon the angels who are close to Allah, and the prophets, and those who follow them of the believers and Muslims."' (Using translation from Nasāʾī 874)  

عَنْ صَلَاةِ رَسُولِ اللهِ ﷺ؟ قَالَ أَيُّكُمْ يُطِيقُ ذَلِكَ قُلْتُ إِنْ لَمْ نُطِقْهُ سَمِعْنَاهُ قَالَ «إِذَا كَانَتِ الشَّمْسُ مِنْ هُنَا كَهَيْئَتِهَا عِنْدَ الْعَصْرِ صَلَّى رَكْعَتَيْنِ فَإِذَا كَانَتْ مِنْ هُنَا كَهَيْئَتِهَا مِنْ هُنَا عِنْدَ الظُّهْرِ صَلَّى أَرْبَعًا وَيُصَلِّي قَبْلَ الظُّهْرِ أَرْبَعًا وَبَعْدَهَا اثْنَتَيْنِ وَيُصَلِّي قَبْلَ الْعَصْرِ أَرْبَعًا يَفْصِلُ بَيْنَ كُلِّ رَكْعَتَيْنِ بِتَسْلِيمٍ عَلَى الْمَلَائِكَةِ الْمُقَرَّبِينَ وَالنَّبِيِّينَ وَمَنِ اتَّبَعَهُمْ مِنَ الْمُؤْمِنِينَ وَالْمُسْلِمِينَ»