Choose they must. The possession of free will, and the perception of opposing objects of choice, either exciting desire, or developing the rational affirmation of obligation to choose, render choice one way or the other inevitable. The law directs how they ought to choose. If they do not choose thus, it must be because they choose otherwise, and not because they do not choose at all. It cannot consist in the choice of moral evil, or sin, as an ultimate end.
Sin is but an element or attribute of choice or intention, or it is intention itself.
Disobedience to moral law cannot consist in self-love. Self-love is simply the constitutional desire of happiness. It is altogether an involuntary state. It has, as a desire, no moral character, any more than has the desire of food. It is no more sinful to desire happiness, and properly to seek it, than it is wrong to desire food, and properly to seek that.