Where is the first prophecy of the 70 year judgement for failing to keep the sabbath to the land?
Tough one. The first reference I can find is:
Lev 26:33-35
"And I will scatter you among the nations, and I will unsheathe the sword after you, and your land shall be a desolation, and your cities shall be a waste.
“Then the land shall enjoy its Sabbaths as long as it lies desolate, while you are in your enemies’ land; then the land shall rest, and enjoy its Sabbaths. As long as it lies desolate it shall have rest, the rest that it did not have on your Sabbaths when you were dwelling in it."