R' Simcha Bunim Sofer quotes a Midrash (which I haven't found, so pls enlighten me if you can locate it) on Pharoah's question (10:8) to Moshe מִ֥י וָמִ֖י הַהֹלְכִֽים -- why the double מִ֥י וָמִ֖י (see Kli Yakar as well)? The Midrash comments that Pharoah challenged Moshe's request as unreasonable given that in the future Bnei Yisrael will one day say מי יעלה לנו בהר ה׳ ומי יקום במקום קדשׁו
What's the connection?
My chavrusa once prepared a whole shiur on this idea of "Mi yaaleh... u'mi yakum." Ascending the mountain is a great achievement, but even harder than making it to the top is sustaining yourself there. I remember as a teenager in camp that there was someone who went min ha'katzeh el ha'katzeh, what today people call flipping out. This guy gave up all his hobbies, all his outside interests, switched his wardrobe to dress pants and white shirts, and went from a background of next to no exposure to learning to doing nothing but learning. It lasted about a year or two, and then he fell back to his old self just as fast as his meteoric rise. There are a lot of people like that, people who get the mi yaaleh part, but then fail in the mi yakum. It's like people who go on these crash diets for a few weeks and lose a ton of weight, but then turn into a balloon again as soon as the diet is over. There is no mi yakum because they focused on the goal of shedding pounds quickly, but not on developing good eating habits that can make the weight loss sustainable. A person needs to go step by step, to grow gradually and adjust and accommodate to each level before trying to climb higher or it will not last.
This was Pharoah's argument. "Lchu na ha'gevarim," let those who are giborim=koveish es yitzro, those who have shown themselves already to be religiously committed, those who have been on top of the mountain for awhile, leave Egypt to serve G-d. But how can you demand that everyone, even those who, until Moshe started making demands, are no different than their Egyptian counterparts -- halalu ovdei avodah zarah v'halalu ovdei avodah zarah -- pick up suddenly and leave? רְא֕וּ כִּ֥י רָעָ֖ה נֶ֥גֶד פְּנֵיכֶֽם -- they people are still attracted to רָעָ֖ה, their same old ways, their same old lifestyle. Even if they go out and have a chag l'Hashem, it's a one time deal and they will quickly revert back to who they are now. Moshe, you are asking for a מי יעלה without considering מי יקום, and it can't work.
Pharoah indeed had a point, as we see time and again from the rebelliousness of Bnei Yisrael in the midbar. Yetzi'as Mitzrayim was a tremendous opportunity, as Hashem brought us up the ladder in one shot, על כנפי נשׁרים, but at the same time it was a tremendous challenge, as מי יעלה demands מי יקום or it is for naught.