Why must we do evangelism? What is the goal? A great many answers to these questions have been put forward. We do it to see people converted, to see them become disciples of Jesus increasingly conformed to his image. We evangelize out of obedience to Christ, love for the lost, and for the glory of God. All of these reasons are good and right. But there's another word that comes to mind, one that we don't always hear associated with evangelism. What is that word? It's worship. Evangelism is about worship.
In the opening chapter of 1 Thessalonians, Paul celebrates the manner in which the the good news first came to the believers in that city. He says that when he first preached the gospel to them, it came "not in word only, but also in power and in the Holy Spirit and with full conviction" (1:5). For Paul, the gospel is about the saving work of God through the death and resurrection of the exalted Lord Jesus Christ (cf. Rom 1:16-17; 1 Cor 1:18-25; 15:1-4). And evangelism, as the announcement of that good news, is a means of grace by which the Holy Spirit works powerfully to produce conviction in the one who hears enabling them to respond with believing obedience to the message they've heard.
But that is not all that Paul celebrates. That means of grace serves a greater end. Near the end of the same chapter he commends the Thessalonians because word about them has spread to other regions. And what were people saying? They were talking about how the Thessalonians had turned "to God from idols" (1:9). Why does Paul get really excited about evangelism? Why did he give his life to evangelizing the Roman Empire? He did it because there were people out there who did not worship the God who raised Jesus from the dead (cf. 1:10). The goal of evangelism is to bring people into the worship of the one living and true God.
One pastor is well-known for saying that, "Mission exists because worship does not." We can easily, and for the same reasons, say that evangelism exists because worship does not. There are great and untold numbers of people who have not yet come into the life-giving worship of the God made known in Jesus of Nazareth. When they do, our evangelistic imperative will come to an end. But until that day, God has granted his people the privilege of announcing the good news of "the one who loved us and gave himself for us." This is our joyful duty until that day.