(ח) וַיָּ֥קָם מֶֽלֶךְ־חָדָ֖שׁ עַל־מִצְרָ֑יִם אֲשֶׁ֥ר לֹֽא־יָדַ֖ע אֶת־יוֹסֵֽף׃
(Ex. 1, 8) Now there rose up a new king over Egypt, who knew not Joseph. Rab and Samuel differ in the explanation of the meaning of this passage. One contends that it means a real new king, while the other says "his decrees were new." According to the one who says that it means a real new king, he infers it because it is written a new. The other one who contends that his decrees were new infers because it is not mentioned that the previous king had died and a new one had become king. But how will the latter explain who knew not Joseph? This means that he pretended not to know Joseph. (Ib., ib. 9)
And he built store cities for Pharaoh. Rab and Samuel differ in the explanation of the above passage. One contends, cities which caused danger to its owners, and the other explains it to mean, cities which caused poverty to its owners; for the Master said elsewhere: "Whoever occupies himself with buildings will at last become poor." (Ib) Pithom and Ra'amses. Rab and Samuel differ in the explanation of this passage, one contends that its real name was Pithom, and the reason it was called Ra'amses, was because one building after the other was crushed (fell in) ; and the other said that its real name was Ra'amses, and the reason it was called Pithom, was because one building after the other was swallowed in the depth. (Ib., ib. 12) But the more they afflicted him, the more he multiplied and the more he spread abroad. It should have been so they multiplied and so they spread abroad? Said R. Simon b. Lakish: "The Holy Spirit predicted to them, saying: "Thus [as it keeps on now] will they multiply and spread abroad." (Ib., ib., ib.) And they felt abhorance because of the children of Israel. From this it may be inferred that the Israelites were like thorns in the eyes of the Egyptians. (Ib., ib. 13) And the Egyptians caused the children of Israel to labor with (Ib. b) rigor. R. Elazar said: "The word b'fa-rech (rigor) means with soft words." R. Samuel b. Nachmeni said: This means rigorously." (Ib., ib. 14) And they made their lives bitter with hard labor in mortar and in bricks and in all manner of labor in the field. Said Raba : "This passage informs us that in the very beginning they started with mortar and in bricks but afterwards with all manner of labor in the field." Besides all their other service, they made them labor with rigor. Said R. Samuel b. Nachmeni in the name of R. Jonathan: "This means that they changed the work of men for women and the work of women for men, and even he who explained the foregoing b'fa-rech differently, will admit that the same word here means rigorously."
ויקם מלך חדש. פירושו כמשמעו בלא תוספת שלא היה מזרע המלוכה. על כן כתיב ויקם כמו כי הקים בני את עבדי
A "new king" means just what it sounds like it should mean-there is no need to add the complication of a new decrees here. "Arose" implies he was not related to the previous king. Therefore “arose” is like (II Samuel 22:8) when Saul exclaims, “no one informs me when my own son sets my servant against me, as is now the case.
Had Pharoah known about Joseph's life, he would have realized that all the attempts to do evil to him - first by the brothers and then by Potiphar - had ultimately been to Joseph's benefit, and it was through these very deeds that he had ascended to his lofty position. Had Pharaoh known this, he would have been afraid to enslave the Jews so as not bring about their ultimate redemption.
Pharaoh knew that Joseph had saved Egypt, but did not care. He did not let the information change his outlook.(Mishnat Rabbi Eliezer) Through much of Jewish history, the people's well-being depended on the goodwill of a ruler. When the leadership changed, the fortunes of the Jewish community often changed as well. Pharaoh begins by refusing to acknowledge Joseph, and later refusing to acknowledge God, saying, "Who is the Eternal that I should heed God?" (Exodus 5:2)