Hadith on Aaron: Mary was called sister of Aaron because of her descent from Prophet Aaron

Mughira ibn Shu’ba reported: When I came to Najran, the Christian monks asked me, “You recite the verse: O sister of Aaron (19:28); whereas Moses was born long before Jesus by such-and-such years.” When I came back to the Messenger of Allah, peace and blessings be upon him, I asked him about it and he said, “Verily, they would name people with the names of prophets and righteous people who had gone before them.”

Source: Sahih Muslim 2135, Grade: Sahih (authentic) according to Imam Muslim

Ibn Kathir reported: Ali ibn Abu Talha and As-Suddi said, “It was said to her: O sister of Aaron (19:28); meaning the brother of Moses, because she was from among his descendants.” Ibn Kathir added, “This is like saying to somebody from the Tamimi tribe: O brother of at-Tamim, or to somebody from the al-Mudari tribe: O brother of Mudar.”

Source: Tafseer Ibn Kathir, verse 19:28

عَنْ الْمُغِيرَةِ بْنِ شُعْبَةَ قَالَ لَمَّا قَدِمْتُ نَجْرَانَ سَأَلُونِي فَقَالُوا إِنَّكُمْ تَقْرَءُونَ يَا أُخْتَ هَارُونَ وَمُوسَى قَبْلَ عِيسَى بِكَذَا وَكَذَا فَلَمَّا قَدِمْتُ عَلَى رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ سَأَلْتُهُ عَنْ ذَلِكَ فَقَالَ إِنَّهُمْ كَانُوا يُسَمُّونَ بِأَنْبِيَائِهِمْ وَالصَّالِحِينَ قَبْلَهُمْ

2135 صحيح مسلم كِتَاب الْآدَابِ تسموا باسمي ولا تكنوا بكنيتي

قال علي بن أبي طلحة والسدي قيل لها يٰأُخْتَ هَـٰرُونَ أي أخي موسى وكانت من نسله؛ كما يقال للتميمي يا أخا تميم وللمضري يا أخا مضر

19:28 التفسير ابن كثير