Hadithcore
Mishkat al-Masabih, 1171

‘Ali said that God's Messenger used to pray four <i>rak’as</i> 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.

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

References1 variant
In-Book Reference
Book 4, Hadith 588