Sahih Muslim
The Book of Pilgrimage (Kitab Al-Hajj)
Book Number: 007 / Hadith Number: 2763
Jabir b. Abdullah (Allah be pleased with them) reported that when Asma' hint Umais gave birth (to a child) in Dhu'I-Hulaifa. Allah's Messenger (may peace be upon him) commanded Abyl Bakr (to convey to her) that she should take a bath and enter Into the state of Ihram.