In Arabic the word "brother" or "sister" has 2 meanings:
1- Blood brother or sister and
2- Brotherhood/sisterhood in clan and faith.
" And unto (the tribe of) A'ad (We sent) their brother, Hud. He said: O my people! Serve Allah. Ye have no other Allah save Him. Will ye not ward off (evil)?" [The Noble Qur'an 7:65].
" And to (the tribe of) Thamud (We sent) their brother Salih. He said: O my people! Serve Allah. Ye have no other Allah save Him. A wonder from your Lord hath come unto you. Lo! this is the camel of Allah, a token unto you; so let her feed in Allah's earth, and touch her not with hurt lest painful torment seize you ". [The Noble Qur'an 7:73]
" And unto Midian (We sent) their brother, Shu'eyb. He said: O my people! Serve Allah. Ye have no other Allah save Him. Lo! a clear proof hath come unto you from your Lord; so give full measure and full weight and wrong not mankind in their goods, and work not confusion in the earth after the fair ordering thereof. That will be better for you, if ye are believers ". [The Noble Qur'an 7:85]
" The 'Ad, Pharaoh, and the brethren of Lut ".[The Noble Qur'an 50:13].
" The Believers are but a single Brotherhood: So make peace and reconciliation between your two (contending) brothers; and fear Allah, that ye may receive Mercy ". [The Noble Qur'an 49:10]
In the Bible, Elizabeth was called daughters of Aaron. Was she literally a daughter of Aaron?
" In the days of Herod, King of Judea, there was a priest named Zechari'ah, of the division of Abi'jah; and he had a wife of the daughters of Aaron, and her name was Elizabeth. [Luke 1:5].
The Christians claim that since the MOTHER of ESAU was REALLY the BIOLOGICAL SISTER of AAROON the Prophet made a "mistake."
However, It is clear that Mary WAS figuratively
a "O SISTER OF AAROON" - WHY?
Because both the Bible and Quran agree she was a LEVITE i.e. a member of the tribe of hereditary "cohens" or "priests" in Judaism. (All
ultimately descendants of Aaroon)
How do I know this? Mary's cousin was Elizabeth
whom we are told "belonged to a priestly family"
(Luke 1:5, 36). See also Quran 3:35-36 (stating
Mary was descendent of priestly line of Imran).
A female descendent of the hereditary priesthood could quite properly be called a "sister of Aaroon!
Mughira b. Shu'ba reported: "When I came to Najran, they (the Christians of Najran) asked me: You read "O sister of Harun (Aaron)" (i. e. Mary) in the Qur'an, whereas Moses was born much before Jesus. When I came back to Allah's Messenger (may peace be upon him) I asked him about that, whereupon he said: The (people of the old age) used to give names (to their persons) after the names of Apostles and pious persons who had gone before them. (Translation of Sahih Muslim, The Book on General Behaviour (Kitab Al-Adab), Book 025, Number 5326)"
As we clearly see from the Saying (Hadith) of our beloved Prophet, this issue was brought to him before and he clearly responded to it. The false claim made against our Prophet about him meaning that Mary was a biological sister of Aaron is clearly refuted.