Leviticus 26:34

Then shall the land rest. God had commanded that the land should rest every seventh year. This seems to have been the case for a time, but the custom later fell into disuse. Doubtless some thought that they might enrich themselves by refusing to let the land rest every seventh year. But as a result they lost the land altogether. God kept account of the time during which the land had been deprived of the Sabbath rest. And when destruction came, with the arrival of the Chaldeans, the land was given “rest” to make up for the time of transgression (2 Chron. 36:21). Seventy years would suggest that for 490 years the land had not kept “her sabbaths.”