As far as I can tell, the majority report of the theological tradition, and especially among Protestant theologians and biblical commentators, is that lying is always wrong, even in the case of the so-called mendacium officiosum, the “officious” or “dutiful lie,” when the goal is to preserve the life or virtue of another while doing no harm to the one deceived.
This seems in many cases to be due to a(n) (over-)reliance on Augustine, who wrote two treatises against lying in addition to his epistolary dispute with Jerome on the topic, and a right desire to maintain that what Scripture reports it does not necessarily endorse: thus when the text reports deception, it is not necessarily endorsing deception. A full discussion would of course require investigation of what the Ninth Commandment requires and forbids, which, as part of the moral law, often determines or helps to determine the exegesis of passages in which deception is used–if all deceit is intrinsically wrong, we can never say, “Let us do evil, that good may come.” And so one would need to determine if that is what the Commandment in fact means. The question of the legitimacy of deceit is especially acute with respect to episodes such as that of the Hebrew midwives in Exodus 1 or Rahab in Joshua 2.
I said above that the majority report seems to be against the mendacium officiosum, but there are exceptions. One is David Chytraeus in his In Exodum ennaratio, in which he notes “the topics especially to be observed” (loci praecipue observandi) in each chapter. The fifth locus in the first chapter is that de mendacio, “on lying”:
De Mendacio, quod est dicere aliquid contra conscientiam iniusta voluntate nocendi. Licet autem in iis rebus, quas dicere non est necesse, aut quarum spontanea manifestatio peccatum est, uti figura, seu propter honestam et iustam causam aliquid occultare et tegere. Sic Obstetrices Aegyptiae recte excusant se, cur non interficiant Ebraeorum infantes.
On lying, which is to say something contrary to conscience with an unjust will of harming [another person]. It is permitted, moreover, in those matters which it is not necessary to speak of or of which the voluntary manifestation is a sin, to use a figure, or to hide and conceal something for an honorable and just cause. Thus the Egyptian midwives1 correctly excuse themselves as to why they do not kill the infants of the Hebrews.2
Note how he defines “lying”: not as “true vs. false” simplicieter, but as speaking against conscience with unjust intent to harm.
For Chytraeus, then, the rewards of the midwives are not in spite of the means they use to save the Hebrew children, as they are for many other commentators, including John Calvin. Of those rewards, Chytraeus says:
Praemia pietatis et beneficentiae erga Ecclesiam. Dominus aedificavit obstetricibus domos, id est, dedit eis numerosam sobolem, auxit eorum familiam, rem familiarem, et omnes partes oeconomiae. Sic domum Abdemelech Aethiopis, qui Ieremiam defendebat, aedificavit Deus. Ita Constantini, Valentiniani, Theodosii, Caroli Magni, et aliorum principum et Ecclesiae Dei Nutriciorum, domos et imperia Deus auxit et defendit.
The rewards of piety and kindness toward the Church. The Lord built houses for the midwives, that is, he gave them numerous offspring, he increased their families, their family property, and all aspects of their household. Thus God build the house of Ebed0melech the Ethiopian, who was defending Jeremiah. Thus God increased and defended the houses and empires of Constantine, Valentinian, Theodosius, Charlemagne, and other princes and nursing-fathers of the Church of God.