Deuteronomy 29:24-27

all the nations will say, ‘Why has the LORD done thus to this land? What caused the heat of this great anger?’ Then people will say, ‘It is because they abandoned the covenant of the LORD, the God of their fathers, which he made with them when he brought them out of the land of Egypt, and went and served other gods and worshiped them, gods whom they had not known and whom he had not allotted to them. Therefore the anger of the LORD was kindled against this land, bringing upon it all the curses written in this book