From “Growing in the character of a disciple”: Chapter 9 – What is ‘the love of the truth’ and why does truth matter so much to God?
Every non-Christian will, one day, have to face Jesus Christ at the Great White Throne Judgment. Then, every lie they have ever told will be publicly exposed. All things will be put right and made straight. Any lies that a non-Christian has ever told will be publicly exposed and corrected there. Therefore they will be humiliated, quite apart from the eternal punishment that will then follow.
So, an unbeliever may appear to get away with a lie today, but it is inevitable that it will, eventually, be fully exposed. There is no doubt about that, and no escape from it. It would be like telling a lie today, knowing that it will be exposed as a lie next week by the Headmaster at school assembly, in front of all the staff and pupils of the school. Wouldn’t it be stupid to tell such a lie today, knowing it will all come out publicly next week?
Why then does it make any difference if the exposure of that lie might be many years in the future? Why should the timescale matter? It will all still be publicly and humiliatingly revealed, whenever it happens. Perhaps you did not realise that before, but you need to realise it now. Let it act as a brake on your tongue. Let the prospect of it keep you from lying as you reflect on the absolute inevitability of being caught and exposed.