he has a very good point and he explained it in the line you omitted.
protection is from Hashem, no question, but that was your answer to his suggestion of weapons, and that is not necessarily enough. His point is that we should understand that protection comes from Hashem, but not to rely on it. If you are ch”v in a dangerous situation, you would be negligent to stand and do nothing, expecting Hashem to sweep you out of trouble. The more protection you make for yourself, the less open the miracle to save you.
According to some, if one does not have the zchusim necessary to take him out of an unnatural circumstance, he may die even if he was not meant to.