Musnad Abu Ya'la al-Mawsili 1:120

Ishaq ibn Isma'il narrated to us, Yahya ibn Abi Bukayr narrated to me, Shu'bah narrated to us, he said: Yazid ibn Khumayr informed me, he said: I heard Sulaym ibn 'Amir narrating from Awsat ibn Isma'il ibn Awsat al-Bajali, from Abu Bakr al-Siddiq, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "You must be truthful, for it is with righteousness, and both of them are in Paradise. And beware of lying, for it is with wickedness, and both of them are in the Fire. Do not cut ties with one another, do not turn your backs on one another, and be, O servants of Allah, brothers, as Allah has commanded you."