Sunan Ibn Majah, Book 1, Hadith 107 (In-Book) ⓘ
It was narrated that 'Abdullah bin Shaqiq said: "I said to 'Aishah: 'Which of the (Prophet's) Companions was most beloved to him?' She said: 'Abu Bakr.' I said: 'Then which of them?' She said: ''Umar.' I said: 'Then which of them?' She said: 'Abu 'Ubaidah.'"
حَدَّثَنَا عَلِيُّ بْنُ مُحَمَّدٍ، حَدَّثَنَا أَبُو أُسَامَةَ، أَخْبَرَنِي الْجُرَيْرِيُّ، عَنْ عَبْدِ اللَّهِ بْنِ شَقِيقٍ، قَالَ قُلْتُ لِعَائِشَةَ أَىُّ أَصْحَابِهِ كَانَ أَحَبَّ إِلَيْهِ قَالَتْ أَبُو بَكْرٍ . قُلْتُ ثُمَّ أَيُّهُمْ قَالَتْ عُمَرُ . قُلْتُ ثُمَّ أَيُّهُمْ قَالَتْ أَبُو عُبَيْدَةَ .
also referenced under: Hadith 102 (Reference) & Volume 1, Book 1, Hadith 102 (DarusSalam)