Missiology is a sort of forced word for the study of missions. The word started to come into use between 1920 and 1925. Combine its “forced” quality and the fairly recent appearance and you get a reason why I couldn’t find it on etymonline for this post.
Nevertheless, here’s the dictionary.com entry:
It is the result of forcing the word “mission” to be married to o-logy for “study of”.
The mission of the church is to go out and spread the news of Christ and His truth. Don’t believe me? Read Matthew 28:16-20. Actually, I’ll just put the entire text below. Your welcome!
Matthew 28:16-20 – The Great Commission
“16 Then the eleven disciples went to Galilee, to the mountain where Jesus had told them to go. 17 When they saw him, they worshiped him; but some doubted. 18 Then Jesus came to them and said, “All authority in heaven and on earth has been given to me. 19 Therefore go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, 20 and teaching them to obey everything I have commanded you. And surely I am with you always, to the very end of the age.”
The very first to be charged with what we call missions today were those we call the Apostles. They were told to go out and make more people like them, disciples of Christ. This is where missions is most clearly given to believers to carry out (though there be other verses).
Today, in many Christian universities and seminaries you can study missiology. A common element to this area of study is in how we consider the target peoples’ culture in our approach to reaching them. History has shown us missionaries with a variety of approaches, each with varying success/failure. A common element in many of the failures is in failing to recognize and consider the culture of the people trying to be reached as it can have powerful impacts on the receiving of God’s truth. Sadly, history has also shown individuals who went with entirely wrong purposes as well.
Nevertheless, culture is not a magic bullet by any means as history also shows us missionaries who acted quite respectfully toward the people they sought (even by that peoples’ standards) but found themselves chased out or even killed. Even in these incidents, we can look back and often see God’s guiding hand as such early events proved to set the stage for later attempts to succeed. It was not uncommon in the past or even recently for the death of a Christian to prick the consciences of the people they were trying to reach, making them more receptive when more Christians appeared with the gospel message.
I will leave this post here. My mind wants to go on dozens of rabbit-tracks with this topic which isn’t any good for a simple defining/introduction article. If you find yourself interested in this topic, I do recommend you research it further as there is much to get into. People even get PhD’s in this are of study so have at it!