Musnad Ahmad 4
It was narrated from Abu Bakr:
that the Prophet (ﷺ) sent him with Soorat Bara'ah (at-Taubah) to the people of Makkah, to say that no mushrik should perform Hajj after this year and no one should circumambulate the Ka'bah naked, and no one would enter Paradise except a Muslim, whoever had a covenant with the Messenger of Allah (ﷺ) for a specific time, it would last until the stated time, and Allah is free from (all) obligations to the Mushrikoon and so is His Messenger (cf. 9:3). He went around doing that for three days, then [the Prophet (ﷺ) said to ‘Ali; “Go and catch up with him; send Abu Bakr back to me and you convey it.” So he did that. And when Abu Bakr carme to the Prophet (ﷺ) , he wept and said: O Messenger of Allah, is there something the matter with me? He said: `There is nothing but good, but I was instructed that no one should convey it except me or a man from my family.”
حَدَّثَنَا وَكِيعٌ، قَالَ قَالَ إِسْرَائِيلُ قَالَ أَبُو إِسْحَاقَ عَنْ زَيْدِ بْنِ يُثَيْعٍ، عَنْ أَبِي بَكْرٍ، أَنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ بَعَثَهُ بِبَرَاءَةٌ لِأَهْلِ مَكَّةَ لَا يَحُجُّ بَعْدَ الْعَامِ مُشْرِكٌ وَلَا يَطُوفُ بِالْبَيْتِ عُرْيَانٌ وَلَا يَدْخُلُ الْجَنَّةَ إِلَّا نَفْسٌ مُسْلِمَةٌ مَنْ كَانَ بَيْنَهُ وَبَيْنَ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ مُدَّةٌ فَأَجَلُهُ إِلَى مُدَّتِهِ وَاللَّهُ بَرِيءٌ مِنْ الْمُشْرِكِينَ وَرَسُولُهُ قَالَ فَسَارَ بِهَا ثَلَاثًا ثُمَّ قَالَ لِعَلِيٍّ رَضِيَ اللَّهُ تَعَالَى عَنْهُ الْحَقْهُ فَرُدَّ عَلَيَّ أَبَا بَكْرٍ وَبَلِّغْهَا أَنْتَ قَالَ فَفَعَلَ قَالَ فَلَمَّا قَدِمَ عَلَى النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ أَبُو بَكْرٍ بَكَى قَالَ يَا رَسُولَ اللَّهِ حَدَثَ فِيَّ شَيْءٌ قَالَ مَا حَدَثَ فِيكَ إِلَّا خَيْرٌ وَلَكِنْ أُمِرْتُ أَنْ لَا يُبَلِّغَهُ إِلَّا أَنَا أَوْ رَجُلٌ مِنِّي‏.‏