Being darkened in their understanding (second point of difference), and thus blind to all that is most vital—ignorant of God, of the way of salvation, of the love of Christ. Even at best the natural understanding cannot discover these things, and when it is not only imperfect but darkened—made more obscure than ever by sin (see after)—its guidance is altogether defective.
It has been said truly that the youngest scholar in a Sunday school that has been taught the elements of the gospel has more light than the wisest of the heathen. Alienated from the life of God because of the ignorance that is in them, because of the hardness of their heart (third point of difference).
Two causes are given for their alienation, viz. ignorance, and hardness of heart, this last being the ultimate cause. Through worldly living, their hearts have become hard, callous, insensible to spiritual influences, perceiving no beauty in Divine things, no preciousness in Divine promises, no excellence in the Divine image; this makes them ignorant, careless, foolish; and such being their state of heart, they are alienated from the life of God, can't bear vital religion, hate the very idea of spiritual and holy service.