Conscience

A witness written on the heart

The New Testament word, suneidēsis (συνείδησις), comes from a verb meaning ‘to know with’: we know what we have done, and that knowledge sits in judgment within us. The Old Testament has no single word for it, but the experience is there: after he cut off the corner of Saul's robe, "David’s conscience was stricken" (1 Samuel 24:5). Paul says that even Gentiles without the law have this witness:

So they show that the work of the law is written on their hearts, their consciences also bearing witness, and their thoughts either accusing or defending them

Romans 2:15

As Matthew Henry puts it, "Conscience is a witness, and first or last will bear witness." Matthew Henry Conscience is the inward testimony of the natural law God has written on every heart, one of the ways of general revelation. When it pricks us, we know we are answerable to someone above ourselves.

But conscience is a witness, not a lawgiver, and a witness damaged by sin. Scripture speaks of consciences "seared with a hot iron" (1 Timothy 4:2), of minds and consciences that are defiled (Titus 1:15), and of a conscience made weak by lack of knowledge (1 Corinthians 8:7). Paul writes, "My conscience is clear, but that does not vindicate me. It is the Lord who judges me" (1 Corinthians 4:4). A quiet conscience is not proof of innocence; conscience must be taught and corrected by God's word.

A clean conscience

Conscience can accuse, but it cannot forgive. The gospel says that Christ does what conscience cannot: "how much more will the blood of Christ … purify our consciences from works of death, so that we may serve the living God!" (Hebrews 9:14). So Paul speaks of "a pure heart, a clear conscience, and a sincere faith" (1 Timothy 1:5) and strives "always to maintain a clear conscience before God and man" (Acts 24:16). To act against conscience is itself sin, for "everything that is not from faith is sin" (Romans 14:23); that is why Paul urges the strong not to wound a weaker brother's conscience.

Medieval theology distinguished an inborn grasp of the first principles of right and wrong from conscience proper, the judgment that applies them to particular acts Aquinas, Summa Theologiae. At Worms in 1521 Martin Luther answered that unless he was convinced by Scripture and plain reason, his conscience was captive to the word of God and he could not recant. The Westminster Confession states the principle:

God alone is Lord of the conscience, and hath left it free from the doctrines and commandments of men which are in anything contrary to his Word, or beside it, in matters of faith or worship.

Westminster Confession 20.2

Where the traditions place the weight

The Catholic Church calls conscience the inmost place where a person is alone with God. One must follow the certain judgment of conscience, it teaches, but conscience must be rightly formed by God's word and the teaching of the church Catechism of the Catholic Church. The Reformation churches stressed that conscience is bound by Scripture alone, so that neither church nor state may bind it in what God's word does not command; the free church traditions, Baptists and Anabaptists among them, pressed early and hard for this liberty of conscience. All agree that conscience belongs to the dignity of a person before God, and needs daily renewing by the word and the Spirit. See Who decides right and wrong? and the lesson God makes himself known.