He That Hath Ears to Hear, Let Him Hear
There comes a point where it is pointless to talk to atheists. It's just one argument after another.
When that point is reached, simply tell them that Jesus died for their sins, and walk away from the "conversation".
For I delivered unto you first of all that which I also received, how that Christ died for our sins according to the scriptures; And that he was buried, and that he rose again the third day according to the scriptures.
- 1 Corinthians 15:3-4 (KJV)
Some people just don't want to hear, and we should respect that.
Check out this YouTube video for more on this.
He that hath ears to hear, let him hear.
- Matthew 11:15 (KJV)