Hadithcore
Mishkat al-Masabih, 1170

Ibn ‘Umar reported God’s Messenger as saying, “God show mercy to a man who prays four <i>rak'as</i> before the afternoon prayer!” Ahmad, Tirmidhi and Abu Dawud transmitted it.

وَعَنِ ابْنِ عُمَرَ قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «رَحِمَ اللَّهُ امْرَءًا صَلَّى قَبْلَ الْعَصْرِ أَرْبَعًا» . رَوَاهُ أَحْمَدُ وَالتِّرْمِذِيُّ

References1 variant
In-Book Reference
Book 4, Hadith 587