:salam2:
Allah says in the most Holy Quran "And Say to the believing women to lower their gaze (from looking at forbidden things), and protect their private parts (from illegal sexual acts) and not to show off their adornment except only that which is apparent (see the explanation below), and to draw their veils all over Juyubihinna" (Surah An-Nur, Verses #30 and #31)
Ibn Abbas (ra) is one of the most learned men of the Sahaba (Companions). Prophet Muhammad s.a.w.s., even prayed for him saying "O Allah, make him acquire a deep understanding of the religion of Islam and instruct him in the meaning and interpretation of things." He with reference to Surah An-Nur “except only that which is apparent” as Ibn Kathir narrated with a Sahih (authentic) chain of narrators, said it’s "The hand, the ring, and the face." Abdullah Ibn Omar Ibn Al-Khattab (ra) said “the face and the two hands”. Anas Ibn Malik (ra) said “the hand and the ring”. Ibn Hazm said: “all of this (statements) are in the highest of accuracy. And so are statements by Ali (ra), Aisha (ra), and other Tabi’een”.
Now you have to think who would understand these verses better than Aisha (ra) the MOST knowledgeable woman in the matters of Islam and the wife of Prophet Muhammad s.a.w.s. ?
Narrated Aisha, Ummul Mu'minin: Asma, daughter of AbuBakr, entered upon the Apostle of Allah s.a.w.s., wearing thin clothes. The Apostle of Allah () turned his attention from her. He said: O Asma', when a woman reaches the age of menstruation, it does not suit her that she displays her parts of body except this and this, and he pointed to her face and hands. (Narrated by Abu Dawood # 4092).
Narrated 'Abdullah bin Abbas: Al-Fadl (his brother) was riding behind Allah's Apostle and a woman from the tribe of Khath'am came and Al-Fadl started looking at her and she started looking at him. The Prophet turned Al-Fadl's face to the other side. The woman said, "O Allah's Apostle! The obligation of Hajj enjoined by Allah on His devotees has become due on my father and he is old and weak, and he cannot sit firm on the Mount; may I perform Hajj on his behalf?" The Prophet replied, "Yes, you may." That happened during the Hajj-al-Wida (of the Prophet). (Narrated by Bukhari # 589, Muslim, and others).
The point is, the woman of Khath'am was in front of the Prophet (sAas) and Fadl ibn Abbas (rAa), neither of whom is mahram for her, AND HER FACE WAS UNCOVERED. How else could Fadl (rAa) have known that she was "beautiful"? What else was he staring at? That she was in ihram is no excuse because if niqab is fard it would still be obligatory for her to veil her face around the Prophet (sAas) and Fadl (rAa). But she did not do so. She was standing there in front of at least two non-mahram men, and her face was plainly visible to them. And the Prophet (sAas) did not tell her to veil her face. He didn't say to her anything like "don't you know that you're supposed to draw your jilbab over your face around men?". All he did was turn Fadl's head away to stop him from staring.