Musnad Ahmad 28:277

Hassan ibn Musa narrated to us, Ibn Lahi'ah narrated to us, Yazid ibn Abi Habib narrated to us, that he heard Abu al-Khayr saying: I heard Abdullah ibn Amr ibn al-As saying: A man said: "O Messenger of Allah, which Islam is best?" He said: "The one from whose tongue and hand the people are safe."