Al-Hakim al-Tirmidhi reported: Bakr ibn Abdullah al-Muzanni said, “Abu Bakr, may Allah be pleased with him, was not favored over people because of an abundance of fasting and prayer. Rather, he was only favored over them because of something that settled in his heart.”
Source: Nawādir al-Uṣūl 1/148
عَن الحكيم الترمذي عَن بكر بن عبد الله الْمُزَنِيّ قَالَ لم يفضل أَبُو بكر رَضِي الله عَنهُ النَّاس بِكَثْرَة صَوْم وَلَا صَلَاة إِنَّمَا فَضلهمْ بِشَيْء كَانَ فِي قلبه
1/148 نوادر الأصول في أحاديث الرسول