The descent of Mordecai and of his niece Esther is disposed of in a few words in the Scripture. But he could trace it all the way back to the Patriarch Jacob, from whom he was forty-five degrees removed. Beside the father of Mordecai, the only ancestor of his who is mentioned by name is Shimei, and he is mentioned for a specific reason. This Shimei is none other then the notorious son of Gera, the rebel who had so scoffed and mocked at David fleeing before Absalom that he would have been killed by Abishai, if David had not generously interfered in his favor.
David's prophetic eye discerned in Shimei the ancestor of Israel's savior in the time of Ahasuerus. For this reason he dealt leniently with him, and on his death-bed he bade his son Solomon reserve vengeance until Shimei should have reached old age and could beget no more children. Thus Mordecai deserves both appellations, the Benjamite and the Judean, for he owed his existence not only to his actual Benjamite forebears on his father's side, but also to the Judean David, who kept his ancestor Shimei alive.