וַיָּ֥קָם מֶֽלֶךְ־חָדָ֖שׁ עַל־מִצְרָ֑יִם אֲשֶׁ֥ר לֹֽא־יָדַ֖ע אֶת־יוֹסֵֽף׃ טוַיֹּ֖אמֶר אֶל־עַמּ֑וֹ הִנֵּ֗ה עַ֚ם בְּנֵ֣י יִשְׂרָאֵ֔ל רַ֥ב וְעָצ֖וּם מִמֶּֽנּוּ׃ יהָ֥בָה נִֽתְחַכְּמָ֖ה ל֑וֹ פֶּן־יִרְבֶּ֗ה וְהָיָ֞ה כִּֽי־תִקְרֶ֤אנָה מִלְחָמָה֙ וְנוֹסַ֤ף גַּם־הוּא֙ עַל־שֹׂ֣נְאֵ֔ינוּ וְנִלְחַם־בָּ֖נוּ וְעָלָ֥ה מִן־הָאָֽרֶץ׃
ויקם מלך חדש NOW THERE AROSE A NEW KING — Rav and Shemuel (two Amoraim or Talmudical teachers) differed in their interpretation of these words. One said that he was really a new king; the other said that it was the same king but he made new edicts (Sotah 11a). אשר לא ידע WHO KNEW NOT [JOSEPH] — he comported himself as though he did not know him (Sotah 11a).
ויקם מלך חדש. פירושו כמשמעו בלא תוספת שלא היה מזרע המלוכה. על כן כתיב ויקם...
A NEW KING AROSE - The interpretation according to its clear implication without embellishment is that the new king was not from the same royal family as the prior king. Therefore it says "and he arose."
ויקם,... וזכרו כי הוא הביא את משפחתו בעצת פרעה ונתן להם אחוזה וחירות לחק עולם, אבל עתה קם מלך חדש שלא ידע את יוסף, ובזה החוקים והחירות שנתן להגרים האלה לא היה להם שום תוקף אצל המלך הזה, ובת"א וקם מלכא חדתא די לא מקיים גזרת יוסף:
...And he had remembered that Yosef brought his family to Egypt on the advice of Pharaoh and given them a place to leave in autonomy as a permanent gift. But now, a new king arose who did not know Yosef, and therefore the rules and autonomy given to the migrants had no force for this new king. In Targum Onkelos (the Aramaic translation of the Torah) it says : and a new king did not uphold the rules of Yosef.
AND A NEW KING AROSE: It would be more expected to have a "different king" written. Rather the implication of a "new king" is that the king's opinions were new. He did not know to recognize all that Yosef did to help the kingdom and his great faithfulness to the kingdom and in this way the king came to suspect the Hebrews.