Sahih Muslim 1210
Sahih Muslim · Book 15: The Book of Pilgrimage · The soundness of Ihram for the woman in Nifas; It is recommended for her to perform Ghusl before entering Ihram, and the same applies to one who is menstruating
حَدَّثَنَا أَبُو غَسَّانَ، مُحَمَّدُ بْنُ عَمْرٍو حَدَّثَنَا جَرِيرُ بْنُ عَبْدِ الْحَمِيدِ ، عَنْ يَحْيَى بْنِ، سَعِيدٍ عَنْ جَعْفَرِ بْنِ مُحَمَّدٍ ، عَنْ أَبِيهِ ، عَنْ جَابِرِ بْنِ عَبْدِ اللَّهِ ، - رضى الله عنهما - فِي حَدِيثِ أَسْمَاءَ بِنْتِ عُمَيْسٍ حِينَ نُفِسَتْ بِذِي الْحُلَيْفَةِ أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم أَمَرَ أَبَا بَكْرٍ - رضى الله عنه - فَأَمَرَهَا أَنْ تَغْتَسِلَ وَتُهِلَّ .
Jabir b. `Abdullah (Allah be pleased with them) reported that when Asma' bint `Umais gave birth (to a child) in Dhu'l-Hulaifa. Allah's Messenger (ﷺ) commanded Abu Bakr (to convey to her) that she should take a bath and enter into the state of Ihram.