Sayyiduna Ka'b bin Asim al-Ash'ari (may Allah be pleased with him) said: I heard the Messenger of Allah (peace and blessings be upon him) delivering a sermon during the Farewell Hajj on the middle day of the Days of Tashriq. He (peace and blessings be upon him) was saying: "Is this not a sacred day?" The Companions said: "Certainly, O Messenger of Allah!" He (peace and blessings be upon him) said: "Then your sanctity towards one another is just like the sanctity of this day of yours. Shall I tell you who the Muslim is? The Muslim is the one from whose tongue and hand the other Muslims are safe. Shall I tell you who the believer is? The believer is the one whom the Muslims trust with their lives and their wealth. And shall I tell you who the emigrant (muhajir) is? The emigrant is the one who abandons the evils that Allah has forbidden him. And a believer is sacred to another believer just as this day is sacred: his flesh is forbidden to him, that he should eat it by backbiting him; his honour is forbidden to him, that he should stain it; his face is forbidden to him, that he should slap it; harming him is forbidden to him; and it is forbidden to push him in such a way that he staggers."
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16449
Sayyiduna Ka'b bin Asim al-Ash'ari (may Allah be pleased with him) said: I saw the Prophet (peace and blessings be upon him) delivering a sermon beside the Jamrah on the middle day of Eid al-Adha.
Hadith Referenceالمعجم الكبير للطبراني / باب الكاف / 16450