How often this phrase has been lifted from the Bible and even depicted in a famous sculpture: "They shall beat their swords into plowshares." It is used internationally to speak of a day when there will be no more war. It would be most helpful if the entire chapter were read instead of lifting only a part of one sentence.
Indeed, the LORD did reveal to Isaiah that such a day is coming. He called it "in the latter days" and three more times as "that day." But in great contrast to the thinking of unbelievers, this is not a day of negotiated peace between the nations. Rather, it refers to the return of the Messiah who will rule and reign over all the nations from Jerusalem.
What will that day look like?
1. Jesus will teach the nations. (v.2-3)
This is not only for the Jews, but "all the nations" will make their way to Jerusalem to be taught how to live for God. Proverbs 16:7-"When a man's ways please the LORD, he makes even his enemies to be at peace with him." The secret to world peace is not pacifism but both parties doing what is right according to God's Word. Without that, sin and greed for power will lead to war.
2. Jesus will judge the nations. (v.4)
As Isaiah will prophesy later in this book, the "government shall be upon his shoulders" as the "Prince of Peace." He will decide between nations and they will obey Him. Psalm 2 tells of the Father offering this position to the Son and encouraging the nations to repent. This is not described as a happy time for those who rebel against Him. Twice, Isaiah predicts, the haughty will be humbled. Insanely, unbelievers will try to hide from "the terror of the LORD."
3. Jesus will be exalted among the nations. (vv.11, 17)
God's judgment is prompted by individuals and nations who refused to bow before His Sovereignty. Humans are incurably prone to worship something or someone. In the attempt to replace the LORD, idols and philosophies of all sorts are generated by Satan to distract people from the truth. But in that day, all the foolishness of sinful thinking will be brought under control and "the LORD alone will be exalted."
The good news is that no one need wait to repent of sin and trying to live apart from God. Isaiah's invitation is to respond now. "Come, let us walk in the light of the LORD." (v.5)