Genesis 3:22; Ecclesiastes 10:20; Romans 2:14-15; Romans 7:7; Acts 24:16; 1 Peter 3:16; 1 Timothy 3:9; 1 Corinthians 8:7; Titus 1:15; 1 Timothy 4:2; John 16:2
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. 3:2222And the Lord God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: (Genesis 3:22)). The above word occurs once in the LXX in Ecclesiastes 10:2020Curse not the king, no not in thy thought; and curse not the rich in thy bedchamber: for a bird of the air shall carry the voice, and that which hath wings shall tell the matter. (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. 2:14-1514For when the Gentiles, which have not the law, do by nature the things contained in the law, these, having not the law, are a law unto themselves: 15Which 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;) (Romans 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. 7:77What shall we say then? Is the law sin? God forbid. Nay, I had not known sin, but by the law: for I had not known lust, except the law had said, Thou shalt not covet. (Romans 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 24:1616And herein do I exercise myself, to have always a conscience void of offence toward God, and toward men. (Acts 24:16)).
Scripture speaks of :
2. A “pure conscience,” which is characterized by the separation from evil (1 Tim. 3:99Holding the mystery of the faith in a pure conscience. (1 Timothy 3:9)).
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 1:1515Unto the pure all things are pure: but unto them that are defiled and unbelieving is nothing pure; but even their mind and conscience is defiled. (Titus 1:15)); and of others who in departing from the faith have their “conscience seared with a hot iron” (1 Tim. 4:22Speaking lies in hypocrisy; having their conscience seared with a hot iron; (1 Timothy 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 16:22They shall put you out of the synagogues: yea, 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.