Musnad Ahmad 30:3338

Yazid narrated to us, he said: Muhammad informed us, from Abu Salamah, from Abu Hurairah, who said: The Messenger of Allah, may Allah bless him and grant him peace, said: Allah, the Mighty and Majestic, said: "I am the Most Merciful (al-Rahman), and it is the womb (al-rahim). I derived for it a name from My name. Whoever maintains it, I will maintain him, and whoever severs it, I will sever him." And He refused [to do otherwise].