Martin Chemntiz. Loci Theologici Vol. 2. Trans. J. A. O. Preus. St. Louis: Concordia Publishing House, 1989. 424-425.
In the third place, because at this point the ques¬tion of ordinary lying is pertinent, we shall note the main categories of this subject. Scripture in a general sense prohibits all lying. Eph. 4:25; Ps. 5:6, "You destroy all those who speak lies." Wisd. of Sol. 1:11, "A lying tongue is a man's destruction." 1 John 2:21, "No lie is of the truth." Ecclus. 7:14, "Refuse ever to tell a lie."
But there are in Scripture certain examples of holy people whose lying must not be rashly con-demned. Abraham in Gen. 12:13 and 20:2; Jacob in Gen. 27:19; Joseph dissimulated before his brothers in Gen. 42:7 and 44:15. Of the midwives in Ex. 1:19 and in v. 21 it says, "The Lord built them houses." Luke 24:28, Christ pretended that He was going farther on. 1 Sam. 21:13, David pretended to be insane. 1 Sam. 16:5, when Samuel was about to anoint David so that Saul would not find out, he pretended that he must go to Bethlehem to make a sacrifice. 2 Kings 10:19, when Jehu was about to kill the prophets of Baal, he pretended that he was going to make a solemn sacrifice to Baal. Thus also Judith in 11:4 ff.; Jael in Judg. 4:18. Joshua in 8:5 pretends to flee, and in Joshua 2:4, Rahab deceives. Ex. 5:3, "We shall make a three-day journey to sacrifice." 1 Sam. 19:13, Michal, the wife of David, frees her husband by lying. 1 Sam. 20:28, Jonathan saves David's life by saying something misleading.
From this arises an argument. Augustine simply says [De Mendacio, 21, MPL 40.516], "Anyone who thinks that there is any kind of lie which is not sin is foolishly deceiving himself." Again [ibid., 6, MPL 40.494], "There is no arrangement, no good purpose, no dispensation whereby permission, human or divine, can be given to tell a lie." Again [ibid., MPL 40.495], "Even if someone flees to you who can be saved from death by your lie, you shall not lie. For it is written, 'The mouth which lies kills the soul,' Wisd. of Sol. 1:11. Thus, since eternal life is lost by lying, we must never lie for the sake of someone's temporal life." And Augustine gives his reasons: (1) Scripture simply and in an all-inclusive way prohibits and condemns all lying. (2) Words have been established, not in order that through them men might deceive one another, but in order that through them they might communicate their thoughts to the understanding of another person. Therefore, to use words for a purpose for which they have not been established, but to deceive, is a sin. Likewise, the commandment of God is that man speak in no other way than he believes in his heart. John says in his First Epistle, 2:21, "He who loves a lie is not of the truth." (3) If a person excuses lying on the ground that sometimes we can help someone by lying, then by the same line of reasoning murders and robberies can take place because sometimes we can help a person by these sins. But when he comes to an explanation for the instances in Scripture which we have mentioned above, he is involved in all kinds of contortions. Sometimes, he says, that for those who are not perfect it is only a venial sin. Sometimes he sets up degrees of lies whereby one lie is more serious than another and yet none is without guilt, although some are not of great guilt. Somewhere he says that things which are said in joking should not be included as sins. Gregory says that it is permitted in the Old Testament but prohibited only in the New Testament. Thus in the case of the midwives in Ex. 1:19, because of the guilt of their lying, their eternal reward was commuted to a temporal compensation in that God caused houses to be built for them. Ambrose brings up this question: God gave Abraham the command to sacrifice his son, yet because he did not want to do it, was that a lie? Jerome gets closer: Sometimes dissimulation is useful and lawful because Christ Himself pretended in Luke 24:28. Even Augustine says [ibid., 4, MPL 40.489], "To conceal the truth is one thing; to say something false or to speak a lie is something else." Others, in order to excuse Abraham for dissimulating before his servants in Gen. 22:5, refer to the mystical sense of the passage. There are many such opinions on this subject in Gratian, Question 22,18 and in Lombard 3.38 [MPL 192.833-35].
It is manifest that this question is not answered by this variety of opinions, but rather consciences are only more disturbed. Thus we must seek a proper explanation from the true sources which can be correctly applied to all cases. This can be properly done on the basis of the definition of lying. We must note how perilous generalizations can be when used as definitions, as when someone says that it is a lie not to tell the truth. Augustine is correct when he says [De Mendacio, 4, MPL 40.491], "A lie is a false indication of the voice with the willful intention of deceiving." The meaning of the Eighth Commandment can be derived from these very words. For the definition of lying which is forbidden and condemned in Scripture, these points are required: (1) Something false must be presented. (2) This arises out of a "double heart," as it says in Ps. 12:2, that is, when the conscience is persuaded that the matter is false which is given out as the truth. For when someone says that he believes a certain thing to be true, even though in itself it is false, this is still not a lie, because it is not done against conscience. Conversely, when someone says something which he believes is false, even though in itself it is true, it is still a lie, because it is said contrary to the conscience of the one saying it. On this basis they make a distinction between lying (mentin) and a lie (mendacium dicere). (3) There must be some will or intention of deceiving. A violation of the Eighth Commandment involves speaking against one's neighbor. (4) It is also a lie, when, although there is no desire to harm one's neighbor, a person speaks out of the vanity or pride of his mind and does not have a credible or honest reason. Statements of this kind are the lies of flattery, boasting, and things of this kind. Chrysostom, In Matt., says, "Even if they do not have lies, whom do they deceive, for they are lying to themselves?" Under the heading of a sin of omission is the case of lying by wickedly withholding the truth when it would be right, useful, and necessary to speak it, with the intention of deceiving and harming someone
From these basic points we can easily settle the question as to whether every lie is a mortal sin. It is a lie to speak falsely when the truth has been covered up, whether because of evil desire to work harm or because of the empty pride of one's own mind. Therefore not every hiding of the truth is a lie. For a lie is not only hiding something, but it involves telling a falsehood instead of the truth. Thus it is not only the concealing of a thing but rather the corrupting of a certain matter, contrary to conscience, something which ought to be said, which constitutes a lie. Therefore this rule is sure and correct: To conceal something for an honest and just cause in matters which need not be said for reasons of right or usefulness, is not a lie. Again, when a willful revelation of something would be a sin, it is not a lie to say or show something else which is indirect, but it is lawful to use figurative language which does not reveal the points under discussion. For example, see 2 Sam. 17:19.
All cases can be evaluated by the use of this rule. Yet the examples of various godly people ought not be imitated indiscriminately. For often in these cases they have fallen into sin out of fear or stupidity. From the basic teaching of the Eighth Commandment we can draw the principle that it does prohibit hiding or distorting that which ought to be said.
This definition is supported by dividing the matter of lying into certain varieties. Augustine lists eight kinds of lying which are cited at great length in Gratian and Lornbard:19 (1) Lying in the teaching of religion. (2) That which not only benefits no one but hurts someone. (3) That which benefits one person in such a way that it hurts someone else. (4) That which is done purely out of the desire to lie and deceive. (5) That which is done from a desire to please. (6) That which hurts no one and profits someone, that is, to avoid hurting his person. (7) That which harms no one and benefits someone in order to avoid harm to his property. (8) That which hurts no one and benefits no one, as in the case of protecting a person from some ailment of his body. Augustine himself correctly brings in this distinction in commenting on Matthew 5, and the scholastics draw from this the commonly held distinction that there are three kinds of lying: malicious, purposeful, and jesting. Thomas adds this distinction," Certain lies are sinful in that they say too much and others that they say too little."