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.”