Motherly love is unconditional. Fatherly love is conditioned.  

Mother is the home, nature, soil, the ocean. Father represents  law and order, discipline, travel and adventure. In fatherly love obedience is  the main virtue, and  disobedience  the main sin.  Mother should have faith in life, hence not be overanxious, and thus not infect the child with her anxiety. Part of her life should be the wish that the child become independent and eventually separate from her.
Father’s love should be guided by principles and expectations; it should be patient and tolerant, rather than threatening and authoritarian. It should give the growing child an increasing sense of competence and eventually permit him to become his own authority and to dispense with that of father.
Motherly conscience says: “There is no misdeed, no crime which could deprive you of my love, of my wish for your life and happiness.” Fatherly conscience says: “You did wrong, you cannot avoid  accepting certain consequences of your wrongdoing, and most of all you must change your ways.
From Erich Fromm: The Art of Loving