Moses and the Old Testament

What do we do when people tell us that the story of Adam and Eve, the flood, the ten commandments and Moses were written in books before the Bible was even written?

We can point people to Jesus’ own testimony that Moses was the inspired writer of the narratives you mentioned. Here are some Bible passages you can include in your response: Matthew 8:4; 19:8; Mark 7:10; 10:3-5; 12:26; Luke 2:22; 5:14; 16:29-31; 24:27; 24:44; John 5:46; 7:19.