Impenitence is a phenomenon of the will, and consists in the will's cleaving to self-indulgence under light. It consists in the will's pertinacious adherence to the gratification of self, in despite of all the light with which the sinner is surrounded. It is not, as has been said, a passive state nor a mere negation, nor the love of sin for its own sake; but it is an active and obstinate state of the will, a determined holding on to that course of self-seeking which constitutes sin, not from a love to sin, but for the sake of the gratification.

"Repentance and Impenitence" p. 368 - Lectures on Systematic Theology (1878)