حَدَّثَنَا أَبُو كُرَيْبٍ، مُحَمَّدُ بْنُ الْعَلاَءِ حَدَّثَنَا أَبُو أُسَامَةَ، عَنْ هِشَامِ بْنِ عُرْوَةَ، عَنْ أَبِيهِ، عَنِ ابْنِ عُمَرَ، قَالَ حَضَرْتُ أَبِي حِينَ أُصِيبَ فَأَثْنَوْا عَلَيْهِ وَقَالُوا جَزَاكَ اللَّهُ خَيْرًا ‏.‏ فَقَالَ رَاغِبٌ وَرَاهِبٌ قَالُوا اسْتَخْلِفْ فَقَالَ أَتَحَمَّلُ أَمْرَكُمْ حَيًّا وَمَيِّتًا لَوَدِدْتُ أَنَّ حَظِّي مِنْهَا الْكَفَافُ لاَ عَلَىَّ وَلاَ لِي فَإِنْ أَسْتَخْلِفْ فَقَدِ اسْتَخْلَفَ مَنْ هُوَ خَيْرٌ مِنِّي - يَعْنِي أَبَا بَكْرٍ - وَإِنْ أَتْرُكْكُمْ فَقَدْ تَرَكَكُمْ مَنْ هُوَ خَيْرٌ مِنِّي رَسُولُ اللَّهِ صلى الله عليه وسلم ‏.‏ قَالَ عَبْدُ اللَّهِ فَعَرَفْتُ أَنَّهُ حِينَ ذَكَرَ رَسُولَ اللَّهِ صلى الله عليه وسلم غَيْرُ مُسْتَخْلِفٍ ‏.‏

It has been narrated on the authority of 'Abdullah b. 'Umar who said: I was present with my father when he was wounded. People praised him and said: May God give you a noble recompense! He said: I am hopeful (of God's mercy) as well as afraid (of His wrath) People said: Appoint anyone as your successor. He said: Should I carry the burden of conducting your affairs in my life as well as in my death? (So far as Caliphate is concerned) I wish I could acquit myself (before the Almighty) in a way that there is neither anything to my credit nor anything to my discredit. If I would appoint my successor, (I would because) one better than me did so. (He meant Abu Bakr.) If I would leave You alone, (I would do so because) one better than me, i. e. the Messenger of Allah (PBUH), did so. 'Abdullah says: When he mentioned the Messenger of Allah (PBUH) I understood that he would not appoint anyone as Caliph. Translation Not Available

Book reference: Sahih Muslim Book 33 Hadith 4485
Web reference: Sahih Muslim Book 20 Hadith 1823 a