1)
What is the meaning of "Mimeni Sir'u"?
1.
Rashi: You will see what I do [and do the same].
2.
Malbim: Do not do until I do first. I will be first, for I will be at the edge of the camp.
2)
Why did he say "Ka'asher E'eseh Ken Ta'asun"? He already said "Mimeni Sir'u v'Chen Ta'asu"?
1.
Malbim: The first one taught to do only after he does. This teaches to do everything that he does.