It is narrated from Sayyiduna Ibn Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The womb (rahm) is a branch that has clung to the protection of the Most Merciful (Rahman). Whoever maintains its ties, Allah will maintain ties with him, and whoever severs it, Allah will sever him."
Hadith Referenceمسند احمد / ومن مسند بني هاشم / 2953