1)
What is the meaning of "ha'Shomerim"?
1.
Rashi: The Chataf Patach under the Hei shows that this is a question. [The test is] will they go in My way?
2)
What is "Derech Hashem"?
1.
Malbim: It is to dispossess the Nochrim and not make a Bris with them.