The man who appears to feel nothing for his own children, but who treats them upon all occasions with unmerited severity and harshness, seems of all brutes the most detestable.
 Adam Smith, The Theory of Moral Sentiments (1759). copy citation

Context

“We blame the excessive fondness and anxiety of a parent, as something which may, in the end, prove hurtful to the child, and which, in the meantime, is excessively inconvenient to the parent; but we easily pardon it, and never regard it with hatred and detestation. But the defect of this usually excessive affection appears always peculiarly odious. The man who appears to feel nothing for his own children, but who treats them upon all occasions with unmerited severity and harshness, seems of all brutes the most detestable. The sense of propriety, so far from requiring us to eradicate altogether that extraordinary sensibility, which we naturally feel for the misfortunes of our nearest connections, is always much more offended by the defect, than it ever is by the excess of that sensibility.” source