What does Deuteronomy 31:17 mean?

When that happens, I'll turn away from them and let disaster hit them. They'll feel abandoned, and all kinds of trouble will come their way. Then they'll say, "All this is happening because God isn't with us anymore." Deuteronomy 31:17 - Modern Text Bible

(God explains that their choices will have real consequences. When they turn away, they'll feel the loss of his protection.)