וְהָיְתָ֤ה אֶֽרֶץ־מִצְרַ֙יִם֙ לִשְׁמָמָ֣ה וְחָרְבָּ֔ה וְיָדְע֖וּ כִּֽי־אֲנִ֣י יְהוָ֑ה יַ֧עַן אָמַ֛ר יְאֹ֥ר לִ֖י וַאֲנִ֥י עָשִֽׂיתִי׃
애굽 땅이 사막과 황무지가 되리니 그들이 나를 여호와인 줄 알리라 네가 스스로 이르기를 이 강은 내 것이라 내가 만들었다 하도다
Da'at Zekenim
יהיו שבע שני רעב, “will be seven consecutive years of famine.” The word יהיו should be understood as a prayer by Joseph, who was aware that actually 42 years of famine had been decreed for Egypt. How did Joseph know this? You will note that the number שבע appeared in Pharaoh’s dream 6 times. Twice seven when Pharaoh had the dream, once with the cows, once with the ears of corn. The same was repeated when he related his dream to his interpreters. It was repeated again when he related the dream to Joseph. Joseph’s prayer achieved that the 42 years which had been decreed were shrunk to only seven years. The arrival of Joseph’s father Yaakov in Egypt and his blessing to Pharaoh reduced the famine further so that it lasted only two years. The 40 years that were chopped off the decree did not disappear but were “paid back” to Egypt in later years as we know from Jeremiah that Egypt experienced 40 years of total drought predicted by that prophet. (Ezekiel 29,9 and 12)