Fallen human beings are perpetually tempted to deny the one true God, and we do so in many ways. Some people make idols out of created things and worship them instead of the Lord (Rom. 1:18–32). Others exalt themselves above our Creator, believing themselves to be gods in their own right or thinking that God does His work primarily for their sake, not His own (Isa. 14:12–20; 43:25). But everyone has followed our first parents' example in trusting the Enemy's lies and not God's Word (Gen. 3:1–7; Rom. 3:23).
The community of Israelites and Judahites in exile was no different. Despite the promises made to Moses (Lev. 26:40–45; Deut. 30:1–10), the exiles had a hard time believing that the Lord would restore His repentant people, as Isaiah foresaw. We know this to be true because Isaiah 40–66 consistently declares Yahweh's strength and faithfulness. Today's passage makes a similar declaration.
Isaiah knew the exiles, who would live about two hundred years after his time, would continue in the sins that led to their captivity. The core failure would be a lack of faith manifesting itself in hypocrisy. Isaiah 48:1–2 charges the exilic community with confessing "the God of Israel, but not in truth or right." Isaiah knew that most exiles would still be drawing near to the Lord with their lips while having hearts far from Him (29:13).
The Lord could have been done with this people, but Isaiah foresaw that He would graciously continue to reveal Himself to Jacob's offspring. Isaiah 45:3–8 contains an extended apologetic as to why the exiles of Judah and Israel should trust God—because He is the one true God, which fact He proved by declaring the future perfectly before it came to pass. The goal of predictive prophecy, said the Lord to His people, was to show them that He was the only God, because images of metal could not foresee what was ahead (vv. 3–5). But Yahweh did, and because His words had come true in the past, the exiles should always trust Him for their future (vv. 6–8).
At the end of the day, however, the Lord's continuing work among His people was not for their sake but His own. He was refining but not destroying them to preserve His own glory (vv. 9–11). If God were to allow His people to be destroyed, the world could charge Him with being as ineffectual in saving Israel and Judah as the pagan deities were in saving their devotees. This could not be, for it would obscure His glory.