When unbelievers ask us why we believe and act the way we do, why we have any hope living in this evil, broken world, we should be ready to answer. (1Pe 3:15) We shouldn’t just give them sentiment either; true faith is based on facts.
Scientific facts, archaeological and historical facts, well-attested to over centuries, provide the groundwork of earnest belief. We don’t believe a certain way just because our parents did, or because friends and family agree. Godly faith isn’t blind; it’s grounded in wisdom and reason. We should be familiar with the factual grounds of our faith and be prepared to provide a reasonable defense.
Perhaps the greatest challenge to our faith will be on moral grounds, why we don’t accept the LGBTQ or Social Justice agenda. Those who’ve invented their own false Christ think He accepts any behavior because He’s too loving to correct or rebuke anyone. They won’t tolerate those who refuse to bow the knee to political correctness.
In the face of such challenges, is it appropriate to begin quoting scripture? If they reject scripture as authoritative, why would they care what it says? The wicked are often expert at finding flaws in arguments, pointing out apparent inconsistencies, and referencing academic/scientific authorities to support their rejection of Christianity. Trying to answer their objections can be very difficult and time consuming, and even well-reasoned answers will be unacceptable to the darkened heart. This approach seldom ends well.
Perhaps it is better to ask them to explain the basis of their own confidence. In my experience, atheists don’t arrive at their position through any clear evidence, but by rejecting false religion: it’s a strawman fallacy. For a moral code, ask them how they know what good and evil are, and why they act as if evil exists. They can’t help but act this way; it’s in their very design. How so?
If they can’t site some scripture somewhere, some official written moral code that isn’t subject to their momentary whim, perhaps Hindu or Buddhist or Muslim, which they’re following earnestly and consistently, they’re simply making up their own morality as they go. Why then should they get so frustrated when they see us (supposedly) doing the same thing? It’s irrational.
And on the rare occasion when an antagonist does follow some documented code of conduct, it’s easy then to ask what evidence they have that this code was revealed by God. If they’re letting some mere mortal set up their moral code, why impose this on others? This isn’t much better than making up our own.
The very existence of the Jewish people proves God exists, and that Torah is His moral code: it’s not Man-made. And the very existence of Christianity proves that Jesus Christ rose from the dead, and he believed in Torah. If they can’t point to any other code with a more compelling factual and historical basis, and they can’t even get close, then why not follow Torah?
Such an approach may cause an unbeliever to consider why they feel so smug and confident in their unbelief, and to begin to question their own faith. Perhaps God would use this to convict them and move them to seek Him. (Ac 17:27)