Wasn't despoiling Egypt a Mitzvah? It was a Mitzvah, but it was a Mitzvah that also brought an earthly benefit. Moshe's wisdom was realizing it was better to be involved in a Mitzvah that had no earthly benefit because such a Mitzvah is on a much higher level. Therefore it says here, he took. The hebrew word for take, Kichah, always refers to raising something up high (Medrash Tanchuma, Bechukosai 3). Moshe raised himself higher when he chose to perform the Mitzvah of retrieving the bones of Yosef.
10 miracles occured for B'nei Yisroel during Krias Yam Suf (the splitting of the sea).
1. The sea split and so did every other gathering of water in the world.
2. The sea became like a canopy above them.
3. The sea split into 12 passages, one for each tribe and they exited through the same path they entered.
4. For B'nei Yisroel, the sea floor was solid like cement, no mud. For the Egyptians, the ground was completely muddy.
5. The water became like bricks, ordered one on top of the next.
6. A warm breeze blew off the walls of water.
7. Edible fruit sprouted from the walls.
8. Potable water flowed from the sea when B'nei Yisroel were thirsty.
9. The walls of water were clear like glass and people could see each other in the different passages.
10. Windows appeared within the walls so people within different passages could talk as they travelled through the water.
The Maharam Shiff explains that the last part of the Mishna is referring back to the first part, Eat bread with salt when you are praiseworthy in this world because you are wealthy.
The Mon could taste like anything. The poor person's Mon was identical to that of a wealthy person, One who collected more did not have extra and one who collected less did not lack (Shmos 16:18). A person who wanted to be on the path of Torah would only want to taste bread with salt in his Mon. This is the meaning of the posuk, in order to test them, to see if they will follow my Torah or not. I will know by the way they want their Mon to taste if they want the path of Torah or not.
If Moshe's raised hands allowed B'nei Yisroel to prevail, why did he lower them?
When B'nei Yisroel turned their hearts towards their Father in Heaven, the hands of Moshe would become stronger and raise up straight. They would gain strength refers to the hands of Moshe. However if Yisroel would turn their hearts away from their Father in Heaven, the hands of Moshe would weaken and fall.
The proper intentions and sincere repentance of the nation provide strength to its leader. For their sake, he is able to bring about success and salvation.