Why was literacy for slaves threat to slave owners

The white Americans didn't want the slaves to learn how to read and write because if they did the slaves would've read the bible and knew that it was about them.

They would've known that Africa was the motherland and that they were the first people on earth and that they were worth more than the white Americans told them. The white Americans wanted to control the slaves and keep them in fear of them that's why they beat them every time they caught a slave trying to read it. Even when the slave pastors would try to have church the white Americans would tell them what to preach and if they didn't do as they said the white Americans would beat them or even kill them.