Heidelberg Catechism · 1563

Q112. What is required in the ninth commandment?

I must not give false testimony against anyone, twist no one's words, not gossip or slander, nor condemn or join in condemning anyone rashly and unheard. Rather, I must avoid all lying and deceit as the devil's own works, under penalty of God's heavy wrath. In court and everywhere else, I must love the truth, speak and confess it honestly, and do what I can to defend and promote my neighbour's honour and reputation.
Answer · Heidelberg Catechism

Scripture proofs

  1. [1]
    Psalms 15

    A Psalm of David. Lord, who shall abide in thy tabernacle? who shall dwell in thy holy hill? He that walketh uprightly, and worketh righteousness, and speaketh the truth in his heart. He that backbiteth not with his tongue, nor doeth evil to his neighbour, nor taketh up a reproach against his neighbour.

    Proverbs 19:5

    A false witness shall not be unpunished, and he that speaketh lies shall not escape.

    Proverbs 19:9

    A false witness shall not be unpunished, and he that speaketh lies shall perish.

    Proverbs 21:28

    A false witness shall perish: but the man that heareth speaketh constantly.

    Matthew 7:1

    Judge not, that ye be not judged.

    Luke 6:37

    Judge not, and ye shall not be judged: condemn not, and ye shall not be condemned: forgive, and ye shall be forgiven:

    Romans 1:28-32

    And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient; Being filled with all unrighteousness, fornication, wickedness, covetousness, maliciousness; full of envy, murder, debate, deceit, malignity; whisperers, Backbiters, haters of God, despiteful, proud, boasters, inventors of evil things, disobedient to parents, …

  2. [2]
    Leviticus 19:11-12

    Ye shall not steal, neither deal falsely, neither lie one to another. And ye shall not swear by my name falsely, neither shalt thou profane the name of thy God: I am the Lord.

    Proverbs 12:22

    Lying lips are abomination to the Lord: but they that deal truly are his delight.

    Proverbs 13:5

    A righteous man hateth lying: but a wicked man is loathsome, and cometh to shame.

    John 8:44

    Ye are of your father the devil, and the lusts of your father ye will do. He was a murderer from the beginning, and abode not in the truth, because there is no truth in him. When he speaketh a lie, he speaketh of his own: for he is a liar, and the father of it.

    Revelation 21:8

    But the fearful, and unbelieving, and the abominable, and murderers, and whoremongers, and sorcerers, and idolaters, and all liars, shall have their part in the lake which burneth with fire and brimstone: which is the second death.

  3. [3]
    1 Corinthians 13:6

    Rejoiceth not in iniquity, but rejoiceth in the truth;

    Ephesians 4:25

    Wherefore putting away lying, speak every man truth with his neighbour: for we are members one of another.

  4. [4]
    1 Peter 3:8-9

    Finally, be ye all of one mind, having compassion one of another, love as brethren, be pitiful, be courteous: Not rendering evil for evil, or railing for railing: but contrariwise blessing; knowing that ye are thereunto called, that ye should inherit a blessing.

    1 Peter 4:8

    And above all things have fervent charity among yourselves: for charity shall cover the multitude of sins.

Proof texts as given in the original; verse text from the King James Version.