Sayyiduna Anas bin Malik (may Allah be pleased with him) said: The two tribes, al-Aws and al-Khazraj, boasted against each other. Al-Aws said: From us are four distinguished men; and al-Khazraj said: From us too are four. Al-Aws said: From us is the one for whom the Throne of the Most Merciful shook, namely Sa'd bin Mu'adh; and from us is the one whose testimony was made equal to the testimony of two men, namely Khuzaymah bin Thabit; and from us is the one whom the angels washed, namely Hanzalah bin al-Rahib; and from us is the one whose flesh was protected by hornets, namely Asim bin Thabit bin al-Aflah. Al-Khazraj said: From us are four who gathered the whole Qur'an in the time of the Messenger of Allah (peace and blessings be upon him), and no one else gathered it besides them: Ubayy bin Ka'b, Mu'adh bin Jabal, Zayd bin Thabit and Abu Zayd. The narrator said: I asked Anas: Who is Abu Zayd? He said: "One of my paternal uncles."
Hadith Referenceالمعجم الكبير للطبراني / باب الحاء / 3475