Sister does not mean a biological sister, for even today Black people call any Black woman around their age sister.
My Family and Me!
I was born in the late 700's to my parents, King Kashta and Pebatma. I was given the birth name of Piankhi, but people just call me Piye... As I followed my father's footsteps in becoming king, I received my throne name Men-kheper-re meaning: "The Manifestation of Re Abides." I have a lovely and charming sister too named Amenerdis I. She was adopted by Shepenwepet I who was "God's Wife of Amun." My other sister, Peksater, is my wife and i love her so!!! I have a dear brother named Shabaka. He will be my successor after I have passed away:(
WRITTEN BY KING PIYE
And Abram went up out of Egypt, he, and his wife, and all that he had, and Lot with him, into the south.
South of Egypt is Sub-saharan Africa.
Now these are the generations of Ishmael, Abraham's son, whom Hagar the Egyptian, Sarah's handmaid, bare unto Abraham:
So the original Arabs are also Black, since Hagar is an Egyptian .