1)
What is "Yetzer Samuch"?
1.
Rashi: [Their thoughts] relied strongly on Hashem. They did not budge from Emunah in Him due to any threat or affliction.
2)
Why will He guard them?
1.
Rashi: Because they trusted in Hashem, it is proper that He 1 guard them, that they will have Shalom.
1
Malbim explains that the verse addresses Shalom, and asks Shalom to guard them.
3)
Why is "Shalom" repeated?
1.
Radak: It is to strengthen the Shalom.