In Act V Scene vii of the play, Macbeth, Macbeth does not want to fight Young Siward because

Macbeth considers him merely a man born of woman whom he can easily destroy, warning him that his name alone would terrify him; however, if this refers to his reluctance to fight in the final battle, it is Macduff whom Macbeth avoids fighting because his soul is already burdened with the blood of Macduff's family.