It is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) that Sayyiduna al-Abbas (may Allah be pleased with him), the uncle of the Messenger of Allah (peace and blessings be upon him), was among those who used to guard him (peace and blessings be upon him). Then, when this verse was revealed: "O Messenger, convey what has been sent down to you from your Lord; and if you do not, then you have not conveyed His message. And Allah will protect you from the people" [Al-Ma'idah: 67], the Messenger of Allah (peace and blessings be upon him) put an end to the guarding.
Imam al-Tabarani (may Allah have mercy on him) said: "No one narrated this hadith from Fudayl bin Marzuq except Mu'alla bin Abd al-Rahman, and this hadith is narrated from Sayyiduna Abu Sa'id al-Khudri (may Allah be pleased with him) only with this chain."
Hadith Referenceالمعجم الأوسط / باب الحاء / 3510
Hadith Takhrij«أخرجه الطبراني فى «الصغير» برقم: 418»