Musnad Ahmad 10:25

'Abd al-Razzaq narrated to us, Ma'mar informed us, from al-Zuhri, Abu Salamah ibn 'Abd al-Rahman narrated to me, that Abu al-Raddad al-Laythi informed him, from 'Abd al-Rahman ibn 'Awf, that he heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "Allah, the Mighty and Majestic, said: 'I am the Most Merciful (al-Rahman). I created the womb (al-rahim) and I derived for it a name from My name. So whoever maintains it, I maintain him, and whoever severs it, I sever him.'"