Musnad Ahmad 1167:51

Yahya ibn Ishaq narrated to us, he said: Ibn Lahi'ah informed us, from Abu al-Aswad, he said: I heard Ubadah ibn al-Muhajir saying: I heard Ibn Abbas saying to Ibn al-Zubayr: "Will you not ask your mother?" He said: So we entered upon his mother, Asma bint Abi Bakr, and she said: "We went out with the Messenger of Allah, may Allah bless him and grant him peace, until when we were at Dhu al-Hulayfah, he said: 'Whoever among you wishes to enter into the state of ihram for Hajj, let him do so, and whoever among you wishes to enter into the state of ihram for Umrah, let him do so.'" Asma said: "And I, Aisha, al-Miqdad, and al-Zubayr were among those who entered into the state of ihram for Umrah."