Jeremiah 17:9 The heart is deceitful above all things, and desperately sick; who can understand it?
Romans 2:15 They show that the work of the law is written on their hearts, while their conscience also bears witness, and their conflicting thoughts accuse or even excuse them
The Effect of Sin: The Fall and the Conscience’s Limitations
The Fall of humanity, as recounted in Genesis 3, dramatically impacted the function of conscience. Sin distorted the human heart and mind, introducing confusion, guilt, and a tendency toward self-justification. While conscience remained, its reliability was compromised. Scripture teaches that the heart can be “deceitful above all things” (Jeremiah 17:9), and thus conscience, though present, is not infallible. Sin can dull sensitivity to wrongdoing, rationalize evil, or even accuse when there is no guilt. The Apostle Paul acknowledges this complexity, noting that even unbelievers possess a conscience that alternately accuses or excuses them (Romans 2:15), but that it is susceptible to the effects of a fallen nature. Thus, the conscience is a powerful guide, but not an ultimate authority. (MacDonald)
