Mishkat al-Masabih 4 Prayer كتاب الصلاة 588

وَعَنْ عَلِيٍّ رَضِيَ اللَّهُ عَنْهُ قَالَ: كَانَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يُصَلِّي قَبْلَ الْعَصْرِ أَرْبَعَ رَكَعَاتٍ يَفْصِلُ بَيْنَهُنَّ بِالتَّسْلِيمِ عَلَى الْمَلَائِكَةِ الْمُقَرَّبِينَ وَمَنْ تَبِعَهُمْ مِنَ الْمُسْلِمِينَ وَالْمُؤمنِينَ “. رَوَاهُ التِّرْمِذِيّ

‘Ali said that God’s Messenger used to pray four rak’as before the afternoon prayer, separating them with a salutation to the angels who are near God’s presence and the Muslims and believers who come after them. Tirmidhi transmitted it.