22. And to holy David indeed it might more justly be said, that he ought not to have been angry; no, not with one however ungrateful and rendering evil for good; yet if, as man, anger did steal over him, he ought not to have let it so prevail, that he should swear to do a thing which either by giving way to his rage he should do, or by breaking his oath leave undone. But to the other, set as he was amid the libidinous frenzy of the Sodomites, who would dare to say, "Although thy guests in thine own house, whither to enter in thou by most violent humanity hast compelled them, be laid hold upon by lewd men, and being deforced be carnally known as women, fear thou not a whit, care for it not a whir, have no dread, no horror, no trembling?" What man, even a companion of those wretches, would dare to say this to the pious host? But assuredly it would be most rightly said, "Do what thou canst, that the thing be not done which thou deservedly fearest: but let not this fear of thine drive thee to do a thing which if thy daughters be willing that it be done unto them, they will through thee do wickedness with the Sodomites, if unwilling, will through thee from the Sodomites suffer violence. Commit not thou a great crime of thine own, while thou dreadest a greater crime of other men; for be the difference as great as thou wilt between thine own and that of others, this will be thine own, that other men's." Unless perchance in defending this man one should so crowd himself into a corner, as to say, "Since to receive a wrong is better than to do one, and those guests were not about to do but to suffer a wrong, that just man chose that his daughters should suffer wrong rather than his guests, acting upon his rights as his daughters' lord; and he knew that it would be no sin in them if the thing were done, because they would but bear them which did the sin, not consenting unto them, and so without sin of their own. In fine, they did not offer themselves (albeit better females than males) to be carnally known instead of those guests, lest they should be rendered guilty, not by the suffering of others' lust, but by consenting of their own will: nor yet did their father permit it to be done unto himself, when they essayed to do it, because he would not betray his guests to them, (albeit there had been less of evil, if it were done to one man than to two;) but as much as he could he resisted, lest himself also should be defiled by any assent of his own, though even if the frenzy of others' lust had prevailed by strength of body, it would not have defiled him so long as he consented not. Now as the daughters sinned not, neither did he sin in their persons, because he was not making them to sin, if they should be deforced against their will, but only to bear them that did the sin. Just as if he should offer his slaves to be beaten by ruffians, that his guests might not suffer the wrong of beating." Of which matter I shall not dispute, because it would take long to argue, whether even a master may justly use his right of power over his slave, so as to cause an unoffending slave to be smitten, that his unoffending friend may not be beaten in his house by violent bad men. But certainly, as concerning David, it is no wise right to say that he ought to have sworn to do a thing which afterwards he would perceive that he ought not to do. Whence it is clear that we ought not to take all that we read to have been done by holy or just men, and transfer the same to morals, but hence too we must learn how widely that saying of the Apostle extends, and even to what persons it reaches: "Brethren, if a man be overtaken in a fault, ye which are spiritual restore such an one in the spirit of meekness, considering thyself also, lest thou be tempted." 
The being overtaken in a fault happens, either while one does not see at the time what is right to be done, or while, seeing it, one is overcome; that is, that a sin is done, either for that the truth is hidden, or for that infirmity compelleth.
 Gal. vi.1 c23. But in all our doings, even good men are very greatly embarrassed in the matter of compensative sins; so that these are not esteemed to be sins, if they have such causes for the which they be done, and in the which it may seem to be rather sin, if they be left undone. And chiefly as concerning lies hath it come to this pass in the opinion of men that those lies are not accounted sins, nay rather are believed to be rightly done, when one tells a lie for the benefit of him for whom it is expedient to be deceived, or lest a person should hurt others, who seems likely to hurt unless he be got rid of by lies. In defense of these kinds of lies, very many examples from holy Scripture are accounted to lend their support. It is not, however, the same thing to hide the truth as it is to utter a lie. For although every one who lies wishes to hide what is true, yet not every one who wishes to hide what is true, tells a lie. For in general we hide truths not by telling a lie, but by holding our peace. For the Lord lied not when He said, "I have many things to say unto you, but ye cannot bear them now."  He held His peace from true things, not spoke false things; for the hearing of which truths He judged them to be less fit. But if He had not indicated this same to them, that is, that they were not able to bear the things which He was unwilling to speak, He would indeed hide nevertheless somewhat of truth but that this may be rightly done we should peradventure not know, or not have so great an example to confirm us. Whence, they who assert that it is sometimes meet to lie, do not conveniently mention that Abraham did this concerning Sarah, whom he said to be his sister. For he did not say, She is not my wife, but he said, "She is my sister;"  because she was in truth so near akin, that she might without a lie be called a sister. Which also afterwards he confirmed, after she had been given back by him who had taken her, answering him and saying, "And indeed she is my sister, by father, not by mother;" that is, by the father's kindred, not the mother's. Somewhat therefore of truth he left untold, not told aught of falsehood, when he left wife untold, and told of sister. This also did his son Isaac: for him too we know to have gotten a wife near of kin.  It is not then a lie, when by silence a true thing is kept back, but when by speech a false thing is put forward.
 John xvi.12  Gen. xx.2, 12
 Gen. xxvi.7, and xxiv