"What must one do to set his conscience at rest? The same thing he does to extinguish the red light on the dashboard. He doesn't take a hammer and smash the red light. Instead, he gets out and lifts the hood to see what is wrong. His problem is not with the light on the dashboard. He is thankful for the light; it has warned him early enough to something about the real problem. Likewise, one's problem is not with his conscience. It is his friend, warning him that there is something wrong with his behavior. There is no emotional problem. One should not try to smash his conscience then. He will not want to put it to sleep by pills or any means that would anesthetize it. In I Timothy 4:2, Paul referred to those who are "seared (cauterized) in their own conscience as with a branding iron." The word "seared" does not speak of the act of branding, but of the result of branding. It refers to the condition of flesh which has been seared with a branding iron and as a result is no longer sensitive to pain. Paul seems to refer to the same phenomenon in Ephesians 4:19 where he speaks of those who are "past feeling" or "callous" (the word indicates inability to feel pain). If the red light were inactivated the driver might be likely to forget about the problem under the hood, which will grow steadily worse until there is a breakdown. The same is true of the man with an inactivated conscience. Such cauterizing of the conscience comes by ignoring its message or by anesthetizing it over a period of time."
-Excerpt from Competent to Counsel, by Jay E. Adams, Ch. 6, p. 95.