God is on a mission

Now the LORD said to Abram, “Go from your country and your kindred and your father's house to the land that I will show you. And I will make of you a great nation, and I will bless you and make your name great, so that you will be a blessing. I will bless those who bless you, and him who dishonors you I will curse, and in you all the families of the earth shall be blessed.”
(Genesis 12:1-3 ESV)

The story of Abraham is not just about God blessing an individual, or a group of people, for their own benefit, but to be a blessing to those around them. The nation of Israel was to show other nations what God is like. Other nations would see something of the nature of God by watching how his followers live together.

O LORD, my strength and my fortress, my refuge in time of distress, to you the nations will come from the ends of the earth and say, "Our fathers possessed nothing but false gods, worthless idols that did them no good.
(Jeremiah 16:19)

Sing to the LORD, all the earth; proclaim his salvation day after day. 24 Declare his glory among the nations, his marvelous deeds among all peoples. 25 For great is the LORD and most worthy of praise; he is to be feared above all gods. 26 For all the gods of the nations are idols, but the LORD made the heavens. 27 Splendor and majesty are before him; strength and joy in his dwelling place. 28 Ascribe to the LORD, O families of nations, ascribe to the LORD glory and strength, 29    ascribe to the LORD the glory due his name. Bring an offering and come before him; worship the LORD in the splendor of his holiness. 30 Tremble before him, all the earth! The world is firmly established; it cannot be moved. 31 Let the heavens rejoice, let the earth be glad; let them say among the nations, "The LORD reigns!"
(1 Chronicles 16:23-31)

In that day you will say: "I will praise you, O LORD. Although you were angry with me, your anger has turned away and you have comforted me. 2    Surely God is my salvation; I will trust and not be afraid. The LORD, the LORD, is my strength and my song; he has become my salvation." 3 With joy you will draw water from the wells of salvation. 4 In that day you will say: "Give thanks to the LORD, call on his name; make known among the nations what he has done, and proclaim that his name is exalted.
(Isaiah 12:1-3)

Through observing and interacting with God’s people, others should learn about God. They should see the worthlessness of their idolatry in comparison to the one true God. The community of disciples exists to show those who are not part of that community that God is glorious, great and worthy of praise. That He is the source of our strength, our fortress and refuge in times of trouble. That He saves. As Isaiah says, our experience of God turning his anger away from us and comforting us should not only cause us to thank God but also to tell others what He has done

And the Word became flesh and dwelt among us, and we have seen his glory, glory as of the only Son from the Father, full of grace and truth.
(John 1:14)

Our mission is not something that God gives us to do for Him, but something that He is already doing. Jesus became a man to carry out God’s rescue plan for people (including me) who didn’t deserve it. He is the ultimate missionary.

16 Now the eleven disciples went to Galilee, to the mountain to which Jesus had directed them. 17 And when they saw him they worshiped him, but some doubted. 18 And Jesus came and said to them, "All authority in heaven and on earth has been given to me. 19 Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age."
(Matthew 28:16-20)

As we have seen earlier, our mission as disciples of Jesus is participate in His mission of making disciples (who make disciples... who make disciples...)

3 I thank my God in all my remembrance of you, 4 always in every prayer of mine for you all making my prayer with joy, 5 because of your partnership in the gospel from the first day until now...
27 Only let your manner of life be worthy of the gospel of Christ, so that whether I come and see you or am absent, I may hear of you that you are standing firm in one spirit, with one mind striving side by side for the faith of the gospel,
(Philippians 1:3-5, 27)

When Paul thinks about the Philippian church, the thing that brings him joy is not their material prosperity, or the enthusiastic nature of their worship services, or the size of their gathering. It is their partnership in the gospel. This partnership is a group of people united around a goal and pursuing it with everything that is within them. It’s not the fellowship that we think takes place over a cup tea after a sunday morning service but it is more like a rugby team at training camp before the world cup or a group of soldiers during basic training - single mindedly working together to achieve a goal. But this is not partnership around any cause, not unity based on similar interests or backgrounds, or even being united around the goal of unity! This is partnership in the gospel. Working as a body to proclaim the gospel to each other and those who haven't heard it. It is a gospel centered community on mission.

After this I looked, and behold, a great multitude that no one could number, from every nation, from all tribes and peoples and languages, standing before the throne and before the Lamb, clothed in white robes, with palm branches in their hands, and crying out with a loud voice, “Salvation belongs to our God who sits on the throne, and to the Lamb!”
(Revelation 7:9-10 ESV)

In eternity, all nations, tribes and people will be represented. “How then will they call on him in whom they have not believed? And how are they to believe in him of whom they have never heard? And how are they to hear without someone preaching?” (Romans 10:14)