Question:

How can I prove to atheists that the Bible is true when some people claim that there were never records that the Egyptians kept Hebrew slaves? Why would there be no such records?


Answer:

See: Egyptian History and the Biblical Record - A Perfect Match

There is evidence of Semites being used as slaves in Egypt. The usual argument is that it wasn't happening in Egypt at the time the Bible mentions it. The thought that our timeline for Egypt's history might be off, doesn't usually occur to people.