If no weapon formed against us shall prosper, then how do you reconcile what the militant Islamic group, ISIS, is doing to Christians in Iraq? How to you explain Christians died on 9-11? I will go in even deeper. What are you going to do with Paul getting beheaded and Peter being killed by an inverted crucifixion? Does not Isaiah 54:17 say none of that will hurt us?
I believe the answer lies within the fact Isaiah was speaking to the nation Judah, not the church. The church was not formed then. Most notably, Isaiah was proclaiming to the Jews, God will restore them from the Babylonian captivity (that came about due to their hard-heartedness). That is what chapter 54 is about. The Hebrew words “weapon” and “form” refer to a long stick with a fashioned end, most likely a spear or sword the Chaldeans for known for using. God is letting Judah know they will be restored, cover the ends of the earth, and no one will be able to wipe them out. Many think this has a double fulfillment for then and the future when the anti-Christ tries to desolate Israel. Also, Isaiah’s book (66 chapters) is a microcosm of the Bible. The first 39 chapters are mostly bad news, but then around chapter 40, the news starts to get good. Notice how a fella named Jesus (also see Isaiah 54:5) shows up around book 40 of the Bible.
Does this support there is no theological principle that can be gleamed? Oh not at all. Our mission today is no matter the tribulation, continue to trust in him who has the power to reestablish a nation, a people, and make their enemies a footstool.