the "weight" of evil tips the scales in our favor

The Midrash connects the pasuk in Mishlei (27:3)

כֹּבֶד אֶבֶן וְנֵטֶל הַחוֹל וְכַעַס אֱוִיל כָּבֵד מִשְּׁנֵיהֶם:

The weight of a stone and burden of sand -- the anger of a fool is heaver than both.

With the "hichbadti es libo" of our parsha using an elaborate play on words. I’ll do my best to make the simple pshat here intelligible in English.

אמר הקדוש ברוך הוא: כבדתי את ישראל בעולם, שנקראו אבן, כמה דתימא (בראשית מט, כד): משם רועה אבן ישראל.
ונטל החול, אלו ישראל, שנמשלו לחול, שנאמר (הושע ב, א): והיה מספר בני ישראל כחול הים, שנטלתי אותם בעולם ואמרתי (זכריה ב, יב): כל הנוגע בהם כנוגע בבבת עינו.
ועמדו והכעיסו לפני, ובקשתי לכלותן ולהשליכן מעל פני, ואמרתי בשביל פרעה הרשע, שלא יאמר לא היה יכול להצילן ועמד עליהן והרגן.
הוי, וכעס אויל כבד משניהם.
הוי, כי אני הכבדתי את לבו:

Bnei Yisrael are called “even,” a rock: “m’sham ro’eh even Yisrael.”  The Midrash reads k-v-d in the pasuk not as referring to the weight of a rock, but like the word kavod, honor -- Hashem has given us, his rock, a place of honor in the world.  We are compared to the sand of the sea; the “burden of sand”alludes to Hashem taking us under his protection.  However, the Jewish people angered G-d and caused him to want to lash out at them.  Were he to do so, Pharoah would claim that G-d does not have the power to protect and save them.  Therefore, G-d holds back his anger.  More than the love G-d has for Bnei Yisrael, what protects us is the foolishness of Pharoah, the “weight” of the chilul Hashem that would be caused by allowing him to make false claims.  In our parsha, Hashem tells Moshe to go to Pharoah, “ki ani hichbadti es libo.”  Again using a play on words, the Midrash associates the “hichbadti” of Pharoah’s heart with the weight of foolishness referred to in Mishlei.

What are Chazal trying to teach us? We wouldn’t know that Pharoah would attribute it to his own power if Bnei Yisrael did not go free, or that that would be a big chilul Hashem?

When life is smooth sailing, then people think that G-d is treating them nicely.  When the going gets tough, then people think that G-d abandoned them and doesn’t care .  The Midrash is telling us that’s not how it works.  Sometimes the biggest tovah Hashem can do is to put a person in hot water.  It’s not Hashem’s love, the kavod he gives us, his promise to protect us, that brought the geulah from Mitzrayim – rather, it’s the fact that Pharaoh at the end of the day can’t win, as that would be a bigger crime than any wrong we could do.  “Ki ANI hichbadti es libo” – Hashem says just like I gave you kavod and protection which you know is l’tovah, I’m the one giving hardening Pharoah’s heart and in doing so am giving you an you an even bigger tovah, because it’s that hardened heart of Pharoah that is your ticket to geulah. 

Unlike the meforshim who learn that the word “kaveid” in the end of the Midrash refers to the “weight” of the chilul Hashem caused by the evildoer, I would suggest that the end of the Midrash is really the same play on words used in the beginning of the passage.  Just like “koved even” refers to something that honors Klal Yisrael, the “ka’as avil” of the evildoer which is “kaveid” means that what appears to be “ka’as avil,” evil, can itself be the vehicle that ultimately brings even greater honor and geulah to Klal Yisrael.