Sahih Muslim Book 32, Hadith Number 6199.
Chapter : Joining the tie of, relationship and prohibition to break it.
Jubair b. Mut’im reported on the authority of his father that Allah’s Messenger (may peace be upon him) said: The severer would not enter Paradise. Ibn Umar said that Sufyan (explained it as): One who severs the tie of kinship would not enter Paradise.