D.A. Carson

"The church is to see itself as an outpost of heaven.  It is a microcosm of the new heaven and the new earth, brought back, as it were, into our temporal sphere.  We are still contaminated by failures, sin, relapses, rebellion, self-centeredness; we are not yest what we ought to be.  But by the grace of God, we are not what we were.  For as long as we are left here, we are to struggle against sin, and anticipate, so far as we are able, what it will be like to live in the untarnished bliss of perfect righteousness.  We are to live with a view to the day of Christ."

D.A. Carson, A Call to Spiritual Reformation, p.137