Mikets תרל”א 1

ענין החלום שכתוב בתורה משבע שני שובע ורעב. הרמז שגם כח הסט”א רק ע”י גלות השפע בתוך ההסתר.
The idea of the 7 years of plenty and the years of famine in Pharaoh’s dream, is to hint to the idea that even the strength of the evil forces are only because the plenty is ‘exiled’ in the hiddenness.
אבל אין להם כח ח”ו מבלעדי חיות השי”ת.
However even the evil forces have no power on their own chas veshalom, aside from the energy of HaShem
וז”ש ותבלענה כו’. רק שלא נודע כו’. ונדמה כאלו יש להם כח ח”ו בעצמותם. ואינו כן.
This is apparent in the dream. Paroh saw seven fat cows swallowed by the seven thin cows-representing the evil forces. Even though they swallowed them nevertheless it was not apparent on the thin cows (they did not get any fatter). This teaches us the seven fat cows were actually there however they were hidden in the evil force. It also seemed as if they had power, however the only energy they had was because they had swallowed the seven fat cows, the sparks of holiness.
והי’ זה להראות לפרעה קודם הגלות. שידע שאף שבנ”י יהיו כבושין תחת ידו. מ”מ אין לו כח נגד השי”ת ובאמת כ’ אשר לא ידע את יוסף ששכח ג”כ בחי’ זו:
This was a lesson for Paroh before the exile of Bnei Yisrael. He should realise that even though Bnei Yisrael are under his jurisdiction, nevertheless Paroh doesn’t have any strength against HaShem. And the truth is that in the end Paroh even forgot this point as it says a new king arose that did not know Yosef, meaning that he forgot this idea and suddenly thought that he was in control.