The following is a compressed version of some of Steve Humble's thoughts; any misrepresentations are due to Brian's editing!
The primary purpose of God has always been to have a people on earth who recognize him as king over their own lives, over all men, and over all things. This people of God are to be formed in God’s character and to live on earth the way God lives in heaven; that is they are to represent (re-present) their king and manifest his kingdom on earth.
After the Fall, God began to build this people when he called Abraham and made covenant with him and his descendants. God’s people, the children of Abraham, were called to be the blessing of God and his reign for all the nations. However, once God had dealt with Israel’s propensity to serve the gods of other peoples, most of Israel turned the focus inward, believing that they were the center and epitome of God’s interest.
But God’s purpose, unveiled in Christ, was to have a people—the followers of Jesus consisting of both Jews and Gentiles—who would represent God throughout the whole earth, a kingdom people dispersed into all nations, manifesting God’s kingdom in their individual lives and in their community with one another. This call to be communities of the king and his kingdom is the substance of the new covenant.
The people of the kingdom are to follow the pattern of life modeled by their King; that is, we are to lay down our lives individually and corporately for the life of the world (John 6). We, the sons of the kingdom, are seed. Seed does not exist to be stored in barns, at least beyond the short run. Some seed goes through death and resurrection like the First Seed and thus the seed is multiplied. Other seed serves as food, giving life to other creatures. The issue is not to build big barns but to sow out the seed.
Like Israel, “churches” can become ends in themselves, whether on the local or the denominational level, often times using their resources to build bigger and bigger barns. The “churches” tend to be self-focused to a great extent, rather than to offer themselves up (individually and corporate) as living sacrifices of worship. A kingdom movement is focused on giving life. A “church” movement tends to be a consumer of life.