הִנְנִ֤י מַמְטִיר֙ כָּעֵ֣ת מָחָ֔ר בָּרָ֖ד כָּבֵ֣ד מְאֹ֑ד אֲשֶׁ֨ר לֹא־הָיָ֤ה כָמֹ֙הוּ֙ בְּמִצְרַ֔יִם לְמִן־הַיּ֥וֹם הִוָּסְדָ֖ה וְעַד־עָֽתָּה׃
Ketahuilah, besok pada waktu seperti ini Aku akan menurunkan hujan es yang sangat dahsyat, yang belum pernah terjadi seperti itu di Mesir sejak hari negeri itu didirikan sampai sekarang.
Ibn Ezra
ולשרים And princes. The ל has no meaning as far as I know. Comp. לאבשלום (1 Chr. 3:2), למן (Ex. 9:18).1Comp. Sepher Harikmah, 100:6: ל is used sometimes to indicate the subject; e.g., Is. 31:1; 1 Sam. 15:22; Deut. 24:5; 1 Chr. 29:6; Ezr. 1:5; Gen. 1:15; or the predicate, e.g., 1 Chr. 1:13; 21:12; 2 Chr. 3:12; 5:12; Jer. 30:12, 15.
Rabbeinu Bahya
Seeing that the Torah did not do so this is proof that Rashi is correct. Moses never said that he would pray only on the morrow. Seeing that already during the plague of frogs Pharaoh acted as if time were not of the essence to him and he wanted the frogs dead or removed only on the following day, Moses took a cue from this when he announced in future that the plagues he would orchestrate would occur on the following day, such as in 8,19. The same occurred again with the plague of hail which Moses also announced as about to occur on the day following his announcement (9,18). The same was true of the plague of pestilence when Moses gave a full day’s warning for the G’d-fearing people to bring their livestock to safety (9,5). The same occurred again when Moses announced the plague of the locusts (10,4).
The reason why Pharaoh did not ask for the frogs to die or disappear immediately was that he thought that the plague had run its course and that by waiting a day he could show up Moses as not having had anything to do with the cessation of that plague. When Moses demonstrated that the frogs would leave when he wanted, he showed that the plague fulfilled the purpose of showing למען תדע כי אין כה' אלוקינו, “so that you’ll know there is no one like the Lord our G’d.”
The reason why Pharaoh did not ask for the frogs to die or disappear immediately was that he thought that the plague had run its course and that by waiting a day he could show up Moses as not having had anything to do with the cessation of that plague. When Moses demonstrated that the frogs would leave when he wanted, he showed that the plague fulfilled the purpose of showing למען תדע כי אין כה' אלוקינו, “so that you’ll know there is no one like the Lord our G’d.”
Rashi
Behold God deals loftily in His power Because His power is great, and one cannot be saved from before Him. Therefore...who is a teacher like Him? When He teaches a sinner to return to Him, He warns Him before the plague because He knows that he cannot beware of His plague, as He would warn Pharaoh concerning each plague (Ex. 8:17), “I shall let loose the beasts of the wilderness upon you etc.”; (ibid. 10:4), “I will bring locusts...tomorrow,” and so all of them. [In contrast,] when a mortal king wishes to wreak vengeance upon his enemies, he comes upon him suddenly, for, if he warns him, he will repent and be saved from him.