1)
Why does it say that He saved them "Lema'an Shmo"?
1.
Radak: Even though they rebelled against him and had little trust in Him, He did for His name, so He will be known among the Goyim.
2.
Malbim: He wanted to avoid Chilul Hashem - "va'A'as Lema'an Shmi l'Vilti Hechel" (Yechezkel 20:9).
2)
Why does it say "Lehodi'a Es Gevuraso"?
1.
Radak: This is like it says "v'Ikavdah b'Pharaoh