4G Mission Theory is an attempt to visualise our remaining task in world mission. It's not the first and I'm not bold enough to claim it is the best, but I do hope that it will be a helpful contribution.
One of the biggest things that 4G Mission Theory offers is a softening of the false dichotomy of local ministry and overseas missions. There has been a huge divided between those who studied theology and those who studied missiology. A divide between minister and missionary. In essence the missionary task has been taken out of the hands of the church and handled by "professionals" in para-church organisations, and the church would hear reports of what was being done on her behalf. Except for when prayer and finances were needed.
As one who worked 15 years in missions I would often feel guilty for trying to direct the church's resources and attention away from itself. And when we appealed for more young people to be sent overseas in missions there was this push back "we can't all go".
I believe 4G Mission Theory has the potential to relieve this "here" vs "there" pressure. ALL FOUR Geographies are equally essential and every mature church fellowship can seek to find involvement in all 4.
The world has changed. Immigration has changed everything as far as reaching the nations. Other organisations have attempted to make exhaustive lists of people groups (ethne) that are still without their own church movement. I applaud this effort, made especially difficult by the English language's lack of a good word for ethne. But geography confuses these lists. Are the Arabs in Argentina a seperate people group? 4G Mission Theory addresses this by acknowledging that geography is not the principal way of defining targets. G3 exists both at home and abroad.
Another change in world missions is the concerning problem of post-christian regions. Are these unreached people groups when they fall below 2%? Again, 4G Mission Theory accounts for this because G2 is both here and abroad.
One of my personal frustrations has been the lack of attention given, even in missions circles to the G4 people groups at the "ends of the earth". Many christians are mistakenly under the impression that as the world modernises these people will automatically come in contact with local churches. My personal passion and bias is for these people groups. I could build an organisation who advocated and taught about these people groups exclusively but I believe the best chance of communicating this need is to help the church find balance in ALL FOUR rather than just becoming another loud and passionate voice.
As recently as a generation ago missions was "from the west - to the rest". Most missions theory still reflects this. But, Korea, Nigeria, Brazil, Philippines and India are huge sending nations, sending missionaries around the globe including to our countries. 4G Mission Theory applies in light of these changes as well. All 4 Geographies are relevant to your own starting point.
I think there is huge potential for 4G Mission Theory to become a project embraced by the church. I think it would be really cool if churches started approaching missions agencies asking for a G4 Missionary to support or approached theological educators asking for training for G3 cross-cultural service here at home.
4G Mission Theory is broad, but it is not watertight. You will never find an definitive list of 3G or 4G nations for example. Neither will I be able to tell you if the Irish Travellers are 2G, 3G, or 4G because I don't know your heart and life experiences or enough about the life of the Travellers. But hopefully asking the question and finding the answers puts us on the track of finding an effective way to reach waiting people in ALL FOUR geographies for Jesus.