I recently went a few rounds with some pretty hardcore atheists, and I quickly discovered that trying to refer to Scripture was absolutely useless because their position is that the Gospels were written by a committee who simply scoured the OT for various prophecies. Then they patched it together and then presented the myth of Jesus. What are the most effective ways to counter this? All I could think of offhand was that utterly squelching Christianity would have been as easy as falling off a log in the face of such silliness. What else could one say to this?
Why would you want to say anything about salvation to “hardcore atheists”? Were they sincerely asking you to help them achieve eternal life?
Jesus said, “Do not give dogs what is sacred; do not throw your pearls to pigs. If you do, they may trample them under their feet, and turn and tear you to pieces” (Matt. 7:6). He also said, “If anyone will not welcome you or listen to your words, leave that home or town and shake the dust off your feet” (Matt. 10:14)
We all need to remember that a “witness” testifies to things he or she believes to be true. A witness is not a debater, or a salesperson, or an antagonist. Trying to persuade people who don’t want to be persuaded achieves nothing and can often be counterproductive. Instead, pray they will encounter the love of Jesus so strongly that they won’t want to live without it.