Concise Bible Dictionary:
The conscious knowledge of good and evil. This resulted from the fall of Adam. He could have had no knowledge of good and evil before any evil was there. It is remarkable that the word conscience does not occur in the Old Testament In the New Testament the word is συνείδησις, lit. “joint-knowledge.” This agrees with what God said of Adam after the fall, “Behold, the man is become as one of us, to know good and evil” (Gen. 3:22). The above word occurs once in the LXX in Ecclesiastes 10:20: “Curse not the king, no not in thy conscience.” This knowledge of good and evil is universal: some of the most benighted heathen, for instance, have owned that they knew such things as stealing were wrong. They are thus “a law to themselves:” their conscience bearing witness and their thoughts accusing or excusing themselves between themselves (Rom. 2:14-15). The law gave more light as to what was right and wrong: Paul said, “I had not had conscience also of lust unless the law had said, Thou shalt not lust” (Rom. 7:7). Christianity brings the conscience into the light of God, fully revealed by His word; the believer is thus exercised to have a conscience void of offense towards God and men. This may be called a “tender conscience” (Acts 24:16).
Scripture speaks of :
1. A “good conscience,” enabling one when accused of evil, to know that the charge is untrue (1 Pet. 3:16).
2. A “pure conscience,” which is characterized by the separation from evil (1 Tim. 3:9).
3. A “weak conscience,” as on the subject of meats, days (1 Cor. 8:7).
4. A “purged conscience.” Through faith in the infinite efficacy of the blood of Christ the believer has no more conscience of sins. This does not mean no consciousness of ever sinning, but that as regards imputation of sins before God, the conscience is purged. Paul speaks of some who have a “defiled mind and conscience” (Titus 1:15); and of others who in departing from the faith have their “conscience seared with a hot iron” (1 Tim. 4:2), that is, a hardened conscience, insensible to that which should touch them to the quick.
Conscience, with the Christian, should be exercised in the sight of God fully revealed in Christ, and be governed by the word, otherwise, on the plea of “conscience,” many actions displeasing to God may be advocated. This is exemplified in the case of Paul before his conversion. He could say that he had lived in all good conscience before God, and yet he had been hauling men and women to prison because they were Christians. Doubtless he did it with an unoffending conscience, according as the Lord stated: “The time cometh, that whosoever killeth you will think that he doeth God service” (John 16:2). Paul’s zeal for Judaism so blinded his eyes that he was unable to recognize in his conscience the God who gave the law, and had sent His Son also; nor to see that God could act outside of it: it was an unenlightened conscience, a zeal without knowledge, by which even the Christian may be led astray.
Strong’s Dictionary of Greek Words:
Transliteration:
suneidesis
Meaning:
from a prolonged form of 4894; co-perception, i.e. moral consciousness
From Anstey’s Doctrinal Definitions:
This is a faculty in man, acquired in the fall (Gen. 3:5-7, 22), whereby he has an inherent, conscious knowledge of good and evil. The word “conscience” appears only once in the Old Testament (Eccl. 10:20 – margin), but the fact of its presence in man is alluded to in a number of places. Proverbs 20:27, for instance, says that it works as “the candle of the Lord searching the inward parts of the belly.” (“Belly” is used as a figure to denote the deepest part of a person’s being.) It is also alluded to as “a still small voice” in man, whereby he knows right and wrong (1 Kings 19:12). Also, when David did something wrong, it says that his heart “smote” him (1 Sam. 24:5; Job 27:6). These things are the effects of the working of the conscience in men.
In the New Testament, the “conscience” is defined as that which bears witness in the thoughts and hearts of men concerning good and evil (Rom. 2:14-15; 7:7). A man is able to condemn another man for his bad conduct, because he has a moral standard in himself (through his conscience) that enables him to judge what is morally right and wrong. In Romans 2:13-15, Paul explains that even though the Gentiles haven’t had the Law of Moses (the Ten Commandments) given to them, they will, if they follow their conscience, “do by nature the things contained in the Law.” This is because the moral standards of God have been written in their hearts. This inward witness is “a law unto themselves.” A person, therefore, does not need a formal law telling him that it is wrong to murder, steal, and commit adultery, etc., before he knows that those things are wrong. The Creator has written on our hearts how we ought to live as responsible, moral beings, and our consciences bear witness to it.
If a man knows his doings are in accord with this inward law, his conscience is “good” (Acts 23:1; 1 Tim. 1:5, 19; Heb. 13:18; 1 Peter 3:16, 21), “pure” (1 Tim. 3:9; 2 Tim. 1:3), and “void of offence” (Acts 24:16). If what he does is not good, his conscience will be “defiled” (Titus 1:15; 1 Cor. 8:7) and “evil” (Heb. 10:22) and it will accuse him of his wrongs. If his life is sustained by evil deeds, his conscience will become “seared” or cauterized (1 Tim. 4:2), and he will become insensible to its accusations. Thus, at that point his conscience is no longer a reliable witness, as seen in those described in Romans 1. However, men with seared consciences are still responsible for what they do.
The gospel brings the conscience of man into the full light of God. It explains the finished work of Christ on the cross, and the person who believes the gospel of his salvation is “sealed” with the Holy Spirit (Eph. 1:13) and is given a “purged” conscience (Heb. 9:14; 10:2). This does not mean that the believer will no longer be conscious of sinning, but as far as the eternal judgment of his sins is concerned, he understands that it has all been taken care of in the atoning work of Christ, and his conscience is forever silenced as to this matter.