Moshe’s greatness and Pharaoh’s stubbornness
ואמרת אליו וגו’ שלח את עמי במדבר והנה לא שמעת עד כה
You shall tell [Pharaoh]: “…Send out my people to the wilderness. Behold, you haven’t listened until ‘koh’”
Just as the Ten Plagues were about to begin, Hashem commanded Moshe to send a message to Pharaoh: “You have been impudent until now. I have commanded you to send out My people from Egypt, and you have refused. You will know that I am G-d through the Ten Plagues. Then you will send out My people”. This is the simple understanding of the verse, which says you, Pharaoh, haven’t listened until כה (until now). However, the Midrashic understanding is Pharaoh, you will not listen to me to send them out until you hear the word “כה” (literally: thus). Before the final plague, the death of the firstborns, Moshe warned Pharaoh: כה אמר יקוק, כחצות הלילה אני יוצא בתוך מצרים ומות כל בכור…, “Thus says Hashem: ‘Around midnight I will go out within Egypt, and all the firstborn shall die …’”. Moshe told Pharaoh only then will you send them out.
However, this second interpretation needs explanation. Other plagues also contained a warning with the word “כה”. What was so novel about using the word “כה” in the last plague? Also, what difference does it make if he began his statement with the word “כה”, or not? What does the word signify such that only when Pharaoh hears it will he agree to let the Jews free from Egypt?
Chazal point out that Moshe and the other prophets throughout history shared something in common. They all used the expression: כה אמר יקוק, “Thus said Hashem”. However, Moshe’s prophecy was also unique. He was able to say זה הדבר, “This is the matter [which Hashem said]”. What this indicates is that only Moshe’s vision of prophecy was like a clear glass, whereas other prophets’ vision of prophecy was like glass which was foggy. Therefore, the other prophets couldn’t say “זה הדבר”, this is the matter Hashem said. It would imply that these are literally the words that Hashem spoke. Rather, they could only say “כה אמר יקוק”, thus said Hashem. Meaning, the prophet heard regarding this matter and it was their job to deliver its message. This is unlike Moshe, whose prophetic vision was so clear, he could cite word for word what Hashem told him. It was as if the Divine Presence was resting in Moshe’s throat as he spoke. Therefore, he could accurately say the words “זה הדבר”.
We see earlier in the parsha that Moshe’s brother Aharon was appointed to be his spokesperson. Moshe had a speech impediment, and didn’t feel he could convince Pharaoh of anything. Hashem’s response was that He would tell Moshe what to say, which Moshe would then whisper to Aharon. Aharon would then tell Pharaoh what G-d’s message was. What comes out from this is when Moshe and Aharon went to meet with Pharaoh, Moshe didn’t speak to Pharaoh at all. Rather he would dictate to Aharon what to tell Pharaoh. This is why the earlier plagues all used the expression כה אמר יקוק, thus said Hashem, and not זה הדבר, this is the matter which Hashem said. Since it was Aharon speaking, and he didn’t reach the level of prophecy of his brother Moshe, he could only say כה אמר יקוק, thus said Hashem. He introduced his prophecy just like the other prophets.
Whenever Pharaoh summoned Moshe, we see Aharon went with him. However, right before the plague of the first born, the verse says that Pharaoh summoned Moshe. It seems he summoned him alone. That’s when Moshe said his final warning to Pharaoh: כה אמר יקוק, כחצות הלילה אני יוצא בתוך מצרים ומות כל בכור…, “Thus says Hashem: ‘Around midnight I will go out within Egypt, and all the firstborn shall die …’”. It was Moshe himself speaking. That means he could have used the expression זה הדבר, this is the matter that Hashem said. Why then did he use the expression כה אמר, thus said Hashem?
The reason is the same as to why Moshe said the plague would occur “around midnight”. Why didn’t he say exactly at midnight? Was he worried Hashem would get delayed? The answer is that Hashem told Moshe the plague would happen at midnight. Moshe himself decided to say around midnight, because he knew who he was dealing with. Pharaoh was incredibly exacting when it came to details. He felt if there was the tiniest imperfection in the plagues, it was proof that they weren’t coming from Hashem. He would assume they were some trick or sorcery on the part of Moshe. This was logical, and in fact the last plague was going to be flawless. The firstborns were going to die exactly at midnight. However, Moshe was worried Pharaoh’s advisors would have faulty instruments to calculate the time. Perhaps they would be a few instants off, and use it as proof that Hashem wasn’t behind the plague. Therefore, to cover his bases, Moshe specifically said “around” midnight. Since Moshe wasn’t quoting Hashem precisely, he could no longer say זה הדבר, this is the matter which Hashem said. He had to say כה אמר יקוק, thus said Hashem.
This is significant as it proves just how far Pharaoh’s heart had become hardened. Despite enduring the devastating plagues, witnessing the unquestionable hand of G-d, confirming that everything Moshe had told them until now came true with absolute precision, a miniscule miscalculation of when midnight fell would throw that all away? Therefore, Moshe had to speak imprecisely and say the plague would occur around midnight? Yes indeed. Consequently, Moshe had to introduce his prophecy with the words כה אמר יקוק, thus said Hashem. This shows how stubborn Pharaoh had become.
Now the Midrashic interpretation of לא שמעת עד כה, you have not listened until כה, makes sense. You Pharaoh will not let the Jewish people go until you hear the words “כה אמר יקוק”, thus said Hashem; until you hear the warning and subsequently experience the death of the firstborns. Moshe was warning Pharaoh, before any of the plagues even started, that his heart will become so hardened, he will become so stubborn, that Moshe will have no choice but to say his prophecy with the words כה אמר יקוק. Moshe informed Pharaoh that they will meet one on one, without Aharon acting as an intermediary. Moshe will be hearing the prophecy straight from Hashem, with absolute clarity. Even so, the prophecy will be imprecise. He will have to say the firstborns will die around midnight. Therefore, he won’t be able to say זה הדבר, this is the matter Hashem said. Rather, כה אמר יקוק, thus said Hashem.
 Based on Be’er Yosef to Exodus 7:16
 Exodus loc. cit.
 Rashi ad. loc.
 Ibid and Lekach Tov ad. loc. We do not have the original Midrash in our possession. See Nachalas Yaakov ad. loc. However, see Zohar II p. 37b
 Exodus 11:4-5
 The plagues of blood (ibid 7:17), frogs (7:26), wild beasts (8:16), pestilence (9:1), hail (9:13) and locusts (10:3)
 Mizrachi to Rashi loc. cit. says the difference is the other plagues only mentioned כה in their warning, whereas the plague of the death of the firstborns mentioned the word כה in the plague itself
 Sifrei Bamidbar 153:2, brought by Rashi to Numbers 30:2
 Sifsei Chachamim ad. loc.
 Yevamos 49b: כל הנביאים נסתכלו באספקלריא שאינה מאירה, משה רבינו נסתכל באספקלריא המאירה
 The oft quoted phrase, השכינה מדברת מתוך גרונו של משה, has its source in the Zohar Rayah Mehemnah 232b
 This explains why Avos 1:1 says קבלה of the Torah by Moshe but not by Yehoshua. See Ruach Chaim ad. loc.
 Exodus 7:1
 Ramban to ibid 6:13, based on Shemos Rabbah 8:3 and Midrash Tanchuma Va’eira § 10; cf. Rashi to Exodus 7:2
 Ibid verse 24
 Ibid 11:4-5. Even though the earlier verses describe Pharaoh banishing Moshe from his palace, this verse was said while he was still before him (Rashi ad. loc.)
 Cf. Gur Aryeh to Numbers loc. cit., who says that only prophecies which related to an eternal mitzvah used the prophetic vision that was like a clear glass. This would allow usage of the phrase זה הדבר. One-time historical prophecies, such as Moshe’s warnings to Pharaoh, didn’t use this clear vision. Thus, they would use the phrase כה אמר יקוק. As well, cf. Malbim to Numbers loc. cit., who says that Moshe at this point wasn’t yet at the level to have his prophetic vision to be like a clear glass. That happened later. Therefore, he could only use the expression כה אמר יקוק. However, the Be’er Yosef must understand like the Tzeidah LaDerech to Exodus 3:6 who says that since the time of the burning bush Moshe’s prophecy had this level of clarity. It’s unclear to me what the position of the Ramban is, since in Exodus 3:5 it sounds like he holds Moshe didn’t attain his level of prophecy until the Mount Sinai, but in Exodus 6:2 it sounds like at that point he had already achieved his heights. The opinion of the Rambam is also unclear to me. The Meshech Chochmah to Exodus 16:9 infers from the Mishneh Torah Hilchos Yesodei HaTorah 7:6 that Moshe’s uniqueness in prophecy, specifically that he didn’t need to prepare for it and was constantly connected to Hashem, started only after the giving of the Torah at Mount Sinai. It could be having the clear prophetic vision goes hand-in-hand with this, and would thus make the Malbim like the Rambam. However, Rav Dovid Cohen infers from the end of Mishneh Torah Hilchos Avodah Zarah Chapter 1 that from the beginning of Moshe’s leadership of the Jews he had his full prophetic powers
 Berachos 4a, brought by Rashi to Exodus 11:4
 I heard from Rabbi Reznick, that the Akeidas Yitzchok explains Hashem hardening Pharaoh’s heart means that He took away Pharaoh’s clarity to see the Hand of G-d. It was so obvious that the plagues were from Hashem, but He gave room to err. An example of this was by the plague of pestilence, where all the Egyptian animals died, but only one from the Jews (based on Exodus 9:7; cf. Shemos Rabbah 11:4). If none from the Jews had died, Pharaoh would have admitted the plagues were from Hashem. However, Hashem had one killed so Pharaoh could be mistaken. Pharaoh saw that one had died, and decided that it couldn’t be from Hashem. This ties in nicely with the Be’er Yosef’s explanation, that if it wasn’t exactly at midnight, it couldn’t be from Hashem. This adds the dimension that Hashem was the cause of Pharaoh’s exactness with the plagues