Thematic Bible: The threatened punishment of israel was sevenfold

And if in spite of all this you still will not listen and be obedient to Me, then I will chastise and discipline you seven times more for your sins. And I will break and humble your pride in your power, and I will make your heavens as iron [yielding no answer, no blessing, no rain] and your earth [as sterile] as brass. And your strength shall be spent in vain, for your land shall not yield its increase, neither shall the trees of the land yield their fruit. read more.
If you walk contrary to Me and will not heed Me, I will bring seven times more plagues upon you, according to your sins.