There will one day be true peace on earth. The apostle Peter wrote:
But according to his promise we are waiting for new heavens and a new earth in which righteousness dwells. (2 Peter 3:13 ESV)
The Bible tells us that Jesus will return to the earth.
“Men of Galilee, why do you stand looking into heaven? This Jesus, who was taken up from you into heaven, will come in the same way as you saw him go into heaven.” (Acts 1:11 ESV)
When Jesus returns, he will come to raise the dead and gather the faithful to himself.
For the Lord himself will descend from heaven with a cry of command, with the voice of an archangel, and with the sound of the trumpet of God. And the dead in Christ will rise first. Then we who are alive, who are left, will be caught up together with them in the clouds to meet the Lord in the air, and so we will always be with the Lord. (1Thessalonians 4:16-17 ESV)
When sin and death have been conquered on the earth, then Christ will have finished his work and the earth will finally be full of the glory of the LORD.
For as by a man came death, by a man has come also the resurrection of the dead. For as in Adam all die, so also in Christ shall all be made alive. But each in his own order: Christ the firstfruits, then at his coming those who belong to Christ. Then comes the end, when he delivers the kingdom to God the Father after destroying every rule and every authority and power. For he must reign until he has put all his enemies under his feet. The last enemy to be destroyed is death. For “God has put all things in subjection under his feet.” But when it says, “all things are put in subjection,” it is plain that he is excepted who put all things in subjection under him. When all things are subjected to him, then the Son himself will also be subjected to him who put all things in subjection under him, that God may be all in all. (1 Corinthians 15:21-28 ESV)
This peace will be brought about by a desire to know the ways of God and commitment to walk in them.
It shall come to pass in the latter days that the mountain of the house of the LORD shall be established as the highest of the mountains, and shall be lifted up above the hills; and all the nations shall flow to it, and many peoples shall come, and say: “Come, let us go up to the mountain of the LORD, to the house of the God of Jacob, that he may teach us his ways and that we may walk in his paths.” For out of Zion shall go the law, and the word of the LORD from Jerusalem. (Isaiah 2:2-3 ESV)
In the end, there will be a new heaven and earth, wiped clean of everything that has polluted it and God will once again dwell with man in a new Garden of Eden.
Then I saw a new heaven and a new earth, for the first heaven and the first earth had passed away, and the sea was no more. And I saw the holy city, new Jerusalem, coming down out of heaven from God, prepared as a bride adorned for her husband. And I heard a loud voice from the throne saying, “Behold, the dwelling place of God is with man. He will dwell with them, and they will be his people, and God himself will be with them as their God. He will wipe away every tear from their eyes, and death shall be no more, neither shall there be mourning, nor crying, nor pain anymore, for the former things have passed away.” (Revelation 21:1-4 ESV)