Extra-Tanachic accounts for Nitzavim prophecy?
In Nitzavim, Devarim 29:23-27 it says:
"all nations will ask, “Why did the LORD do thus to this land? Wherefore that awful wrath?” They will be told, “Because they forsook the covenant that the LORD, God of their fathers, made with them when He freed them from the land of Egypt; they turned to the service of other gods and worshiped them, gods whom they had not experienced and whom He had not allotted to them. So the LORD was incensed at that land and brought upon it all the curses recorded in this book.The LORD uprooted them from their soil in anger, fury, and great wrath, and cast them into another land, as is still the case.”"
I was wondering if there are any external historical sources that point to non-Jews saying this about the exiled Jews. I know Christians say this, but I'm not sure it's quite the same, because they conflate our covenant with Hashem with a supposed covenant with Jesus.