The unbeliever starts his arguments with the assumption that the bible is untrue. We must not begin there. We begin with the trustworthiness of Jesus. The biblical record is clear with regard to the character of our Lord. If they assert that Jesus is a liar, ask them to prove it from the Scriptures. If their desire is to debate intelligently, should they not first be familiar with the material they want to disprove?
If Jesus is untrustworthy then sure, dismiss the Scriptures. But if he is not, then listen to them and listen to him.
“What evidence do you have that Jesus is someone who should not be trusted? That’s a big claim.”