– Missionaries are an elite type of Christian who go and work for a mission’s agency and write prayer letters in order to generate financial support
– Mission is something you “go on.” It’s an option for young people who want to go abroad for a short period of time.
I want to suggest that this isn’t helped by two misunderstandings of Matthew 28:16-20. First of all, well meaning people have suggested that verse 19 should be translated: “as you go, make disciples.” The basis of this is that “Make disciples” is the only imperative in the passage, the word we normally translate with the imperative “Go” is a participle which we would normally translate as “going.” In other words, our first call is not to “Go…” This is not a command to leave one place and go elsewhere. This means you can be on a mission here.
There are two problems with this interpretation. The first is that it doesn’t work grammatically. As Daniel Wallace explains, this is an example of “Attendant Circumstances” where an aorist participle ‘piggybacks’ on the main verb that follows. In other words, the participle is to be treated in the same way as the imperative. Grammatically, we are correct to treat “Go” and a command just like “make disciples.”
Secondly, I don’t think that “As you go, make disciples” really does help to encourage a missional motivation. It feels rather haphazard, sloppy and incidental to me. It sounds a bit like “Get on with your life and if you get an opportunity then maybe try and encourage someone to follow Jesus.”
The other problem with how we have treated Matthew 28:1-20 is that we have taken this command and we have made it into something emotive and optional for individuals. How do I know if God is calling me to mission? Well, I know if my heart responds subjectively to the words of this passage or when someone preaches on it. It is all about whether or not I’ve heard a call.
I believe this is to miss entirely the point of the passage. Remember that these are some of Jesus’ last words before he returns to Heaven. He has died and has risen, taking the penalty for sin and defeating death. He tells his disciples that he is speaking as the one who has all authority. He is gathering together and he is commissioning the apostles, those who will provide the foundation for the church to be built on (Ephesians 2:20). In other words, because this is foundational, it is a command that the life and purpose of the whole church throughout history is rooted in. This is not an invitation to some Christians individually, this is a command to the whole church, corporately.
Now, also consider how the words here echo the commission to humanity in Genesis 1:28 (sometimes referred to as the Cultural commandment).
“Be fruitful and multiply. Fill the earth and govern it. Reign over the fish in the sea, the birds in the sky, and all the animals that scurry along the ground.”
The first Adam was given authority to fill and subdue the whole earth so that all creatures were to be obedient to him. The new Adam has been given authority to rule, subdue and fill the earth and so he is commissioning his followers to act on his behalf. This is a command for fledgling church to move out and to fill the earth, making disciples so that all around the world, people are to be called as obedient worshippers of the true King.
This is not about what we do incidentally as we go on any random journey. Rather, Jesus is setting in motion an outward motion from Jerusalem, into Judea and Samaria and to the ends of the earth.
This means that the church is constantly called to be moving out and onwards until all have had the opportunity to hear. This is why Paul was passionate to preach the Gospel where it hadn’t been heard.
I want to suggest that this means first of all, that we need to preach this passage corporately to congregations, are they collectively fulfilling the Great Commission. It means that I must consider my role and responsibilities within the context of the local church and not in isolation. It does mean that we should proactively be looking to set people apart and send them onwards to places where there is great Gospel need.
 See Wallace, Greek Grammar Beyond the Basics, 645.