Pastor David L. Brown, Ph.D.
The Greek word for conscience is suneidhsiv suneidesis (soon-i’-day-sis),
which means "a knowing with oneself." The conscience is the
knowledge of good and evil which God has put in man.
Proverbs 20:27 "The spirit of man is the candle of the LORD, searching all the inward parts of the belly."
Adam Clark gives a good explanation of this passage. He says, "God has given to every man a mind, which he so enlightens by his own Spirit, that the man knows how to distinguish good from evil; and conscience, which springs from this, searches the inmost recesses of the soul."
Matthew Henry writes, "Conscience, that noble faculty, is God's deputy in the soul; it is a candle not only lighted by him, but lighted for him. The Father of spirits is therefore called the Father of lights. 2. It is a discovering light. By the help of reason we come to know men, to judge of their characters, and dive into their designs; by the help of conscience we come to know ourselves. The spirit of a man has a self-consciousness it searches into the dispositions and affections of the soul, praises what is good, condemns what is otherwise, and judges of the thoughts and intents of the heart. This is the office, this the power, of conscience, which we are therefore concerned to get rightly informed and to keep void of offence.
Romans 2:15 "Which show the work of the law written in their hearts, their conscience also bearing witness, and their thoughts the mean while accusing or else excusing one another;)"
As in the previous verse, the word conscience means the judgment of the mind respecting right and wrong; or the judgment which the mind passes on the morality or immorality of its own actions, when it instantly approves or condemns them.
The design of our conscience is to serve the purposes of an ever present witness of our conduct. The conscience compels a person to judge his own doings, and therefore motivates him to honorable deeds. The conscience gives comfort and peace when we do right, and deters us from evil actions by making us, whether we want to or no, our own executioner. (See John 8:9; Acts 23:1; 24:16; Romans 9:1; 1 Timothy 1:5). By nature, because of the conscience God has put in man, every man thus approves or condemns his own acts; and there is not a profounder principle of the divine administration, than thus compelling every man to pronounce on the moral character of his own conduct. However, I should also note that our conscience may be enlightened or unenlightened, and its use may be greatly perverted by false opinions as we will see later in this study.
Greek scholar says this: The phrase "seared with a hot iron" is but one word in the Greek - kauthriazw kauteriazo (kow-tay-ree-ad’-zo). That is where we get our word cauterize. The ones referred to here are branded in their own conscience. The metaphor is from the practice of branding slaves or criminals, the latter on the brow. These deceivers are not acting under delusion, but deliberately, and against their conscience. They wear the form of godliness, and contradict their profession by their crooked conduct (2Ti_3:5). The brand is not on their brow, but on their conscience. Robertson says, their conscience is "branded with the mark of Satan.
The Greek word translated is miainw miaino (me-ah’-ee-no), which means to dye with another colour, to stain.