There is a shift here to the second person. This may mean 1) the writer begins speaking to the people of Israel or 2) the writer is quoting another person speaking to the writer. (See: [[rc://en/ta/man/translate/figs-123person]])
Here to "slumber" means he would stop protecting. The negative form strengthens the statement. Alternate translation: "God will not fall asleep and stop protecting you" or "God will always protect you" (See: [[rc://en/ta/man/translate/figs-metonymy]] and [[rc://en/ta/man/translate/figs-doublenegatives]])