If anything should stick with us after reading the Old Testament, it is the fact that our Creator is an exceedingly patient God. Israel rebelled time after time, and time after time our Lord forgave His people and stayed His wrath before it could wipe out the nation (Num. 21:4–9; 1 Kings 21:25–29). But God’s patience with Israel ended, and He finally sent the Israelites into exile on account of flagrant, unrepentant sin (2 Kings 17:7–23; 25:1–21).
We can hardly imagine the trauma of this event. Even the faithful remnant wondered whether the Lord’s plan to save the world through Abraham’s seed had gone off course. Since Israel had failed so miserably, how could peace between God and His children ever be restored (Lam. 5:21–22)? Was the Lord truly sovereign if godless, pagan nations freely raped and pillaged the Israelites (Hab. 1)?
Through Isaiah the prophet, the Lord answered these questions. He would intervene to cleanse the nation of its uncleanness. He would act to prove His eternal dominion, sending messengers to announce His reign over all (Isa. 52:1–7). Of course, this prophecy is fulfilled in the coming of the kingdom of God in the person and work of Christ, which is echoed, with Isaiah’s words, in today’s passage.
Most ancient warfare consisted of hand-to-hand combat between soldiers after long marches to the battlefield. Thus, Roman soldiers required footwear that could sustain their feet as they marched and give them solid footing in a fight. The halfboot called the caliga met these very needs. For spiritual warfare, the gospel of peace fulfills the same purposes for the soldier of Christ. The announcement that God reigns and has reconciled Himself in Jesus to believers sustains us in the long march of the Christian life. It allows us to keep going even when things are so bad that we doubt whether the Lord really is looking out for us.
This gospel also provides solid footing from which we can grapple with Satan. We easily get discouraged with our own spiritual growth, but the truth of what God has done in Christ readies us to repent when we fall and return to the battle with vigor. The gospel gives us, Matthew Henry comments, “a resolved frame of heart which will enable us to walk with a steady pace in the way of religion.”