The Book of Virtue, Good Manners and Joining of the Ties of Relationship (Kitab Al-Birr was-Salat-I-wa'l-Adab)
Muslim :: Book 32 : Hadith 6209
Anas reported Allah's Apostle (may peace be upon him) as saying: Nurse no grudge, nurse no aversion and do not sever ties of kinship and live like fellow-brothers as servants of Allah. This hadith has been narrated on the authority of Shu'ba with the same chain of transmitters but with this addition:" As Allah has commanded you."