The story of the surah At-Taubah

It was narrated from Abu Bakr that the prophet (a.s.) sent him to the people of mecca with verses of surah At-Taubah : no polytheist should perform Hajj after this year and no one should  circumambulate the Kaaba nakedly and no one would enter the Paradise except Muslims . Whoever has a covenant with the prophet for a specific time, his covenant would be valid until the stated time. And Allah and his messenger are free from the polytheists (9:3). While Abu Bakr was on his way, the prophet 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 came to the prophet (a.s.) he wept and said: “O messenger of Allah, has something happened concerning me?”
The Prophet (a.s.) said to him, “Nothing has happened concerning you except good, but I have been ordered (by Allah) that no one should convey it except me or a man from me.”[1]

1.  Musnad, Ahmed Hanbal, vol 1, p 3, h 4.Sunan, al-Tirmdhi, vol 13, p 164-165.Tafsir, al-Tabari, vol 10, p 46