I saw an atheist respond on a post on social media saying,
“How can we know there is a God? Prove it. Not just using the Bible.”

I am not entirely sure if he means, “do not use the bible at all, or use the bible with other non-bible proofs.”

If taken the first way, then the equivalent for me to say the same thing back to him would be like this, “prove to me that evolution is true, but do not use your sensations (empiricism).” An atheist or evolutionist would not accept this because the knowledge of their worldview comes from empiricism.  Without using empiricism, then they have no knowledge about anything. Without their epistemology their worldview is without knowledge. Yet, they demand that we prove our Christian worldview without using the bible, which is the only source of our knowledge. Without the bible there is no knowledge for our worldview about any topic. The bible says that it alone is the source of knowledge (the bible even denies empiricism), and so if we use the bible we can only use the bible for knowledge. There is no dual epistemology in Christianity.

Thus, if meant the second way, then the bible would not allow us to use any other epistemology. Any other source of knowledge would be an anti-Christian source of knowledge. When the opponent is asking us to use other proofs for knowledge other than the Scripture, they are asking to deny the bible at the same time. If we do this, then we have already lost the debate because we have already denied our God and our worldview’s source of knowledge.

 Since the opponent is using empiricism as their source of knowledge, then what they likely mean by “proving Christian with non-biblical knowledge,” means they want us to use so-called empirical proofs for Christianity.  As just said, to do this, since the bible denies empiricism, means we deny Christianity if we use empiricism. Also, empiricism is logically irrational. To infer knowledge from sensation is a never-ending category fallacy. Observation is logically irrational. All conclusions from empiricism and observations are a non-sequitur fallacy. Thus, no matter how good you think your empirical proofs are, they can never logically prove God. Every conclusion from empiricism to God would be a non-sequitur fallacy. For example, the type of existence we sense and observe is not immutable and eternal. Thus, to conclude God’s type of existence from sensation is like saying “All cats are animals, therefore, rocks are yellow.”  The demand to use empirical proofs, is a demand to use a standard of knowledge, that cannot prove any statement about reality. Not only can empiricism not give proof for Christianity, but it also cannot give proof for what is the color red, what is a cloud or what is a rock. Also since Empiricism is irrational, then to hybrid it with the Scripture would be to hybrid the irrational with rational. It would discredit the bible as if the bible is ok with being irrational and stupid. Also what one senses and observes contradicts the bible, and so you have a dual epistemology that contradicts one another. This would make knowledge impossible.

To turn the tables, what if I made a similar demand on the atheist or agnostic by saying, “don’t only use empiricism to prove evolution, but use the bible to give proofs.” The bible obviously contradicts evolution, and many things about their worldview based on their sensations. They would not accept such a demand from me, because they do not accept the bible as a source of knowledge and they know it also contradicts their own worldview.  Likewise, we do not accept empiricism as a source of knowledge. If they want to demand we use their empiricism they need to prove that their epistemology makes knowledge possible. Do not let them bully you with their irrational demands. Rather attack their demands. Attack their standard of empiricism.