It is narrated from Hazrat Aisha (may Allah be pleased with her) that sometimes the Prophet (peace and blessings be upon him) would be in a state of impurity by choice in the morning, then he would perform ghusl and go for prayer, and I would listen to his recitation, and on that day the Prophet (peace and blessings be upon him) would be fasting.
Hadith Referenceمسند احمد / مسند النساء / 24429
Hadith Gradingحکم دارالسلام:حديث صحيح، وهذا إسناد اختلف فيه على الشعبي