Musnad Abu Ya'la al-Mawsili 7:7

Abu Khaythama narrated to us, Yazid bin Harun narrated to us, Hisham al-Dastawa'i informed us, from Yahya bin Abi Kathir, from Ibrahim bin Abdullah bin Qariz, that his father narrated to him that he entered upon Abd al-Rahman bin Awf to visit him. Abd al-Rahman said to him, "May your ties of kinship be maintained. I heard the Messenger of Allah, peace and blessings of Allah be upon him, say: 'Allah said: I am the Most Merciful (al-Rahman), and it is the womb (al-rahm). I derived its name from My name. Whoever maintains it, I maintain him, and whoever severs it, I sever him,' or he said, 'I cut him off.'"