There is only one way there will be peace between warring nations, tribes, and families, and that is for the combatants to accept the fact that they are indeed at war with the Lord of Lords. It is in His household, and nowhere else, that peace is possible:
Ephesians 2:11–22 (ESV)11 Therefore remember that at one time you Gentiles in the flesh, called “the uncircumcision” by what is called the circumcision, which is made in the flesh by hands— 12 remember that you were at that time separated from Christ, alienated from the commonwealth of Israel and strangers to the covenants of promise, having no hope and without God in the world. 13 But now in Christ Jesus you who once were far off have been brought near by the blood of Christ. 14 For he himself is our peace, who has made us both one and has broken down in his flesh the dividing wall of hostility 15 by abolishing the law of commandments expressed in ordinances, that he might create in himself one new man in place of the two, so making peace, 16 and might reconcile us both to God in one body through the cross, thereby killing the hostility. 17 And he came and preached peace to you who were far off and peace to those who were near. 18 For through him we both have access in one Spirit to the Father. 19 So then you are no longer strangers and aliens, but you are fellow citizens with the saints and members of the household of God, 20 built on the foundation of the apostles and prophets, Christ Jesus himself being the cornerstone, 21 in whom the whole structure, being joined together, grows into a holy temple in the Lord. 22 In him you also are being built together into a dwelling place for God by the Spirit.
There is only one people of God.
Colossians 3:5–11 (ESV)5 Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry. 6 On account of these the wrath of God is coming. 7 In these you too once walked, when you were living in them. 8 But now you must put them all away: anger, wrath, malice, slander, and obscene talk from your mouth. 9 Do not lie to one another, seeing that you have put off the old self with its practices 10 and have put on the new self, which is being renewed in knowledge after the image of its creator. 11 Here there is not Greek and Jew, circumcised and uncircumcised, barbarian, Scythian, slave, free; but Christ is all, and in all.
Note then, that the new self, always being renewed, is a place where tribal, national, political, economic and ethnic differences melt away. Religious differences (Islam, Judaism, Baha’i, and Christianity, for example) fade away as it is only in Christ that this renewal is possible. Muslims and Baha’is must reject their false prophets; Jews must cease rejecting their Messiah. All must bow to Jesus as Lord (Philippians 2:9-11, 9 Therefore God has highly exalted him and bestowed on him the name that is above every name, 10 so that at the name of Jesus every knee should bow, in heaven and on earth and under the earth, 11 and every tongue confess that Jesus Christ is Lord, to the glory of God the Father.”)
Without submission to Christ, there will be no peace.