In his book The Mark of the Christian Schaeffer points out the great Commandment to love God and neighbor is at the core of our message and it must be lived out if two things are to occur. First, if men are to know that we are Christ’s disciples, there must be the humble preference toward one another that Jesus demonstrated to the disciples when he washed their feet in (John 13). Love among the brothers lets the watching world see if we actually belong to Jesus or not.
We may very well be his, but if our actions are contradictory then the unbeliever has the right given by God to judge us. This kind of life is costly, painful and accompanied by great loss, but our love for the Savior and for the lost must be what motivates us.
Second, we must be unified with believers so that our evangelistic endeavors are not hindered and the world may know that the Father sent the Son (John 17). This unity must be evident in word and in deed. Even when there are differences among us, and there will be, it’s critical that forgiveness, repentance, humility and kindness be evident when we part ways with our brothers and sisters.
This unity, according to Schaeffer, is not organizational, nor our mystical union with Him, it’s not our positional unity in Christ, not even a legal unity before Him. But it’s a real, observable, practical unity that practices both God’s holiness and love. Schaeffer rightly accentuates that this unity is never to be separated from His propositional truth (scripture) for it is these propositions that believers are called to live out before the world.