When Umm al-Mu'mineen Aisha (may Allah be pleased with her) learned that Ibn Umar (may Allah be pleased with them both) was narrating that the Prophet (peace and blessings be upon him) said that the month is of 29 days, she objected to this and said: May Allah forgive Abdur Rahman, the Prophet (peace and blessings be upon him) did not say this; rather, he said that sometimes the month is of 29 days.
Hadith Referenceمسند احمد / مسند النساء / 26067
Hadith Gradingحکم دارالسلام:حديث صحيح وإسناده كسابقه