The real answer to this question, of course is the work of conviction and renewal by the Holy Spirit in their heart.
But what do hardened atheists say when asked this question?
This is what atheist Peter Boghossian writes in his book A Manual for Creating Atheists:
“…if I walked outside at night and all of the stars were organized to read, “I am God communicating with you, believe in Me!” and every human being worldwide witnessed this in their native language, this would be suggestive (but far from conclusive as it’s a perception and could be a delusion).”
On Real Time with Bill Maher, Maher has a humorous response to what it would take for him to believe:
“Jesus Christ coming down from the sky during the halftime show at the Super Bowl and turning nachos into bread and fish.”
Delight in Truth would argue that some of these atheists would reject Jesus even if He came down during the Super Bowl and performed a physical miracle. Follow the conversations Jesus has with His opponents in John 6 and John 8. Despite the miracles He was doing in their midst, they still did not believe in Him. In fact, they wanted to kill Him. In the same way we have hardened people today who hate God (even though they claim he does not exists).
Clearly pharaoh did not believe in God despite the exceptional miracles performed through Moses… and in our case, Maher would have us think that he would believe in Jesus if he saw nachos turn into bread… This is an abominable proposition in the very least.
Why do atheistic activists fight with such fervor against the concept of a monotheistic God, especially the God of the Bible? When was the last time you saw an anti-theist mock an eastern religion? They focus on Christianity and Jesus because that is where the truth is, and the truth bothers them. They have no problem with Buddhism and other polytheistic religions, but they go after the Judeo-Christian beliefs.
Because they love sin.
God’s moral standard is perfect and they reject it in favor of their own system of so-called morality. They do this in order to numb their God-given conscience and continue to sin.
The next time an atheist or anti-theist challenges you, ask him why he fights so hard against a God whom he claims does not exist…