Question:
What if they don’t believe the Bible (but they believe there’s a God)?
Answer:
All you can do is put the Word before them. It takes God to open them up to it, and He uses His Word which is powerful to do that.
“For the word of God is living and powerful, and sharper than any two-edged sword, piercing even to the division of soul and spirit, and of joints and marrow, and is a discerner of the thoughts and intents of the heart. And there is no creature hidden from His sight, but all things are naked and open to the eyes of Him to whom we must give account” (Hebrews 4:12, 13).