"The reader, by contemplating Adam and Eve in innocency, and afterwards in guilt, will perceive in the facts of their case, the nature of a good conscience, and of an evil one. When they rejoiced in 'the answer of a good conscience,' they were destitute of shame and fear. They could stand naked in God's presence unabashed; and, instead of trembling at His voice, they rejoiced to hear it as the harbinger of good things. It was then pure and undefiled, being devoid of all conscience of sin. They were then of the truth, living in obedience to it as expressed in the law; and therefore their hearts were assured before Him. No doubts and fears oppressed them then. But mark the change that afterwards came over them. When they lost their good conscience, terror seized upon them at the voice of God, and shame possessed their souls; and they sought to get out of His sight, and to remove as far from Him as possible. Now, what was the cause of this? There is but one answer that can be given, and that is--SIN.
Sin then takes away 'the answer of a good conscience towards God,' and converts it into an evil conscience; which may be certainly known to exist, when the subject of it is ashamed of the truth, and harassed by 'doubts and fears.' They are ashamed of the truth, who, being enlightened, feel themselves condemned; or, being ignorant, apprehend it. Such, on account of unbelief, or of 'a dead faith' may well be ashamed and afraid; for to be ashamed of God's truth is to be ashamed of His wisdom and power. People of this description proscribe all conversation about the truth as unfashionable, and vulgar; or as calculated to disturb the peace of the family circle; others, again, make a great outcry against controversy as dangerous to religion; as though God's truth could be planted in the hearts of men, already prepossessed by God's enemy, without controversy; others subjected to the timidity of sin, reduce everything to opinion, and inculcate 'charity'; not that they are more liberal and kind than other people; but they fear lest their own nakedness may be discovered, and 'men see their shame'; while another class of bashful professors cry out, "Disturb not that which is quiet which is a capital maxim for a rotten cause, especially where its subversion would break up all "vested interests,' and pecuniary emoluments. So it is; while 'the righteous are bold as a lion, the wicked flee when no man pursueth' (Proverbs 28:1). Sinners, however 'pious' they may be reputed to be, are invariably cowards; they are ashamed of a bold stand for their own profession; and afraid of an independent and impartial examination of the law and the testimony of God...
Understanding then, that sin, or the transgression of God's law, evinced by doubts, fears and shamefacedness, is the morbid principle of an evil conscience, what is the obvious indication to be fulfilled in its removal? The answer is, blot out the sin, and the conscience of the patient will be cured. The morbid phenomena will disappear, and 'the answer of a good conscience toward God' (1 Peter 3:21) remain. From the nature of things, it is obvious, that the sinner cannot cure himself; though superstition has taught him to attempt it by fastings, and penances, and all 'the voluntary humility and vain deceit,' inculcated by 'the blind.'...
Men have not yet learned the lesson, that all they are called upon by God to do, is to believe His word and obey His laws. He requires nothing more at their hands than this. If they neither believe nor do; or, believe, but do not obey, they are evil doers, and at enmity with Him. He asks men for actions, not words; for He will judge them 'according to their works' in the light of His law; and not according to their suppositious feelings, and traditions. The reason why He will not permit men to prescribe for their own moral evils, is, because He is the Physician, they the lepers; He their Sovereign, they the rebels against His law." (Elpis Israel, 14th ed., page 85-86.)
"An evil conscience is made manifest by the truth, and is evinced by shame and by 'doubts and fears.'" (Elpis Israel, 14th ed.)