When Jesus returned to heaven after His resurrection, He left His followers explicit instructions. They were both for the people who were there with Him that day and for every follower of Jesus who would come after them. He said, “Go and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, and teaching them to obey everything I have commanded you” (Matthew 28:19–20, New International Version). This instruction is known as the “Great Commission” because these words represent a critical assignment for the church as His people await His return.

(Definition from www.cru.org)

An identifiable group of people distinguished by a distinct culture, language, or social class who lack a community of Christians able to evangelize the rest of the people group without outside help. The only opportunity for the people group to hear about salvation is through an “external witness.” Most missiologists consider 2% of the population becoming Christ followers as the “tipping point” at which the group is generally considered “reached” with the Gospel.

(Definition from www.globalfrontiermissions.org)