http://www.guidedones.com/metapage/frq/Aisha.htm Muhammad pbuh got married with Zainab after she was divorce by her husband Zaid because:(1)it is the implementa tion of God's instruction as spoken in the holy qur'an (2)in jahiliyah era somone was prohibited to marry with his/her ad opted son/daughter.so Allah decided against with the old rule (3)adopted son/daughter is not the same with his/her own chil dren so the real inheritance is only for his/.her own children excluding his/her adopted son/daughter. (4)adopted son/ daughter has no heir right,he/she only can get a certain part (maximum one third) of his/her adopted father's wealth if it is written in a testament or spoken with at least 4 witness es.(5) between counsin is halal or allowed to get married.
