Published in the bulletin of Holy Ghost Catholic Church in Knoxville, TN, on 13th Sunday of Ordinary Time.

My dear Parishioners,
Peace! There are ten (10) “In Brief” articles in the Catechism of the Catholic Church addressing the Eighth Commandment of the Decalogue, ‘You shall not bear false witness.’ The following is a reflection on CCC 2504.
The Eighth Commandment of God, ‘You shall not bear false witness’ seems clear and straightforward enough: don’t lie (cf. Exodus 20;16; Mark 10:19)! There are, however, both positive and negative aspects of the Eighth Commandment. The positive side of this commandment of God is to tell the truth, the whole truth and nothing but the truth (cf. Matthew 5:37). Another way we could posit this commandment positively is to bear witness to the truth. The Hebrew words edh, edhah, and anah together with the Greek word martus all translate roughly into the English language as “witness.” The martyrs from the apostolic age, like John the Baptist, Peter and Paul down through the ages, Thomas More (1478–1535), John Fisher (1496–1535), Charles Lwanga (1860–1886), Maria Goretti (1890–1902), even to our own day Edith Stein (Theresa Benedict of the Cross, 1891–1942) and the more than 21 Coptic Martyrs of ISIS (15 February, 2015) bear witness to the truth of the Faith. There are more than one hundred verses in Sacred Scripture which highlight the importance of always bearing true and authentic witness and rejecting the false sort (cf. Isaiah 55:4; Jeremiah 29:23; 42:5; Matthew 15:18–19; 24:14; John 1:7–8, 15; 3:11; 5:31–32, 36–37). We have been made and redeemed by Him who is the way, the truth and the life (cf. John 14:6). As such we are also made for the truth. We have a right to the truth and sin against justice when we speak falsehoods. Whenever we would speak falsehoods we stray from God’s path of holiness, justice and truth (cf. Ephesians 4:24). The devil is the father of lies and we do his bidding whenever we lie or commit any other sins (cf. John 8:44; Proverbs 24:16). We are warned in Sacred Scripture that ‘much sinning can not be avoided in a flood of words’ (Proverbs 10:19).
For his part, Saint Thomas Aquinas, OP (+1274) treats various injuries done through speech in his Summa Theologiae II-II, Q. 67–76. Vices contrary to the Eighth Commandment include but are not limited to reviling, backbiting, talebearing, derision, and cursing. Our friends at the Oxford University Press Dictionary can help us to understand better the various nuances. Consider that the verb “revile” is to criticize in an abusive or scornful way, that is, not constructive criticism. Backbiting is form of malicious talk about someone who is absent and thereby not able to defend themselves and their honor. Someone who is a talebearer either maliciously gossips or reveals secrets. To be contemptuous in either ridicule or mockery is to be derisive. To curse is not only to use vulgarity but may also refer to solemn utterances intending to invoke supernatural powers to inflict harm or punishment on someone or something.
God bless you!
Father John Arthur Orr