Abu Bakr al-Marrudhi reported: I heard Ahmad ibn Hanbal, may Allah have mercy on him, mentioning the Caliph al-Mutawakkil and he said, “Indeed, I pray for his righteousness and well-being.”
Source: al-Sunnah li-Abī Bakr al-Khallāl 16
عَنْ أَبِي بَكْرٍ الْمَرُّوذِيُّ قَالَ سَمِعْتُ أَحْمَدَ بْنَ حَنْبَلٍ رَحِمَهُ اللَّهُ وَذَكَرَ الْخَلِيفَةَ الْمُتَوَكِّلَ فَقَال إِنِّي لَأَدْعُو لَهُ بِالصَّلَاحِ وَالْعَافِيَةِ
1/84 السنة لأبي بكر بن الخلال