In addition, I don't want to trust just my own intellect, which is my tendency. Where spiritual matters are concerned, as much as I can I want to rely on the Word of God. If it is undogmatic, I want to be undogmatic. If it is clear, there I want to take a stand.
Outright, I am of the opinion that lying is not justified. But rather than start from that presupposition and give a list of proofs, I want to try and use scripture to gain an understanding. Scripture first, then hypotheses. Of course, my biases probably will show through, but I hope as a whole the logic will be unblemised.
What does the Bible say about lying?
A few passages come to mind.
Exodus 20:16 - You shall not bear false witness against your neighbor.
Titus 1:2 - in hope of eternal life, which God, who never lies, promised before the ages began.
Heb 6:18 - so that by two unchangeable things, in which it is impossible for God to lie, we who have fled for refuge might have strong encouragement to hold fast to the hope set before us.
Rev 21:8 8 But as for the cowardly, the faithless, the detestable, as for murderers, the sexually immoral, sorcerers, idolaters, and all liars, their portion will be in the lake that burns with fire and sulfur, which is the second death.
There are a lot more passages about this throughout scripture, but I think these are sufficient to get an idea that we are commanded not to lie, and that lying is s sin.
God is a God of truth. But as His children, we we are urged to imitate God.
1 Cor 11:1 - Be imitators of me, as I am of Christ.
1 Peter 1:16 - since it is written, “You shall be holy, for I am holy.”
God is our standard for morality. If he is perfectly holy, then we are called to be perfectly holy (whether we can be is not the issue, what we are commanded is). Our sanctification is the process of us becoming like Christ in all his perfection.
The standard is very high. Immediately I realize I cannot attain it. But the difficulty does not mean I stop working out my salvation with fear and trembling. Why? Because it is GOD who is at work in me, not my own effort, so that I can will and act for his good pleasure. I'm not alone in this endeavour (Phil 2:12,13), This is a wonderful manifestation of Grace.
Hang on you say, what about the exceptions? Well, I'm trying to do this a step at a time, and exceptions or complications, however you want to call it, will come later.
So what is a lie? Starting with the bare bone definition, a lie is an active action. You lie simply when you speak what is not true. Even when we speak of "not telling the truth" we are usually not talking about a passive witholding of information, but of untruth being spoken. This is the first aspect of the issue that I want to deal with.
So far, my simple mind is devoid of further issue and I'm happy to submit to scripture - speaking untruth is forbidden. I want to be like Jesus, and this is his demand. I cannot lie. the issue is so far uncomplicated.