MAY PEOPLES SERVE YOU. These are the children of Noah. AND MAY NATIONS BOW DOWN TO YOU. These are the children of Keturah. Thus: BE MASTER OVER YOUR BROTHERS. These are the children of Ishmael. AND MAY YOUR MOTHER'S CHILDREN BOW DOWN TO YOU. These are the children of Esau. THOSE WHO CURSE YOU, CURSED. This is Balaam and his colleagues. AND THOSE WHO BLESS YOU, BLESSED. This is Moses and his colleagues.
Isaac's Blessing of Jacob Decoded Clause by Clause
Midrash Tanchuma Buber, Toldot 16:7
יעבדוך עמים אלו בני נח, וישתחוו לך לאומרים אלו בני קטורה, הוי גביר לאחיך אלו בני ישמעאל, וישתחוו לך בני אמך אלו בני עשו, אורריך ארור זה בלעם וחביריו, ומברכיך ברוך זה משה וחביריו.