The straightest road to social gospel runs through profound mystical experience. The paradox of true mysticism is that individual experience leads to social passion, that the nonuseful engenders the greatest utility. If we seek a social gospel, we must find it most deeply rooted in the most mystic way. Love of God and love of neighbor are not two commandments, but one. It is the highest experience of the mystic, when the soul of man is known to be one with God himself, that utility drops off and flutters away, useless, to earth, that world-shaking consciousness of mankind in need arises in one and he knows himself to be the channel of Divine Life. The birth of true mysticism brings with it the birthday of the widest social gospel. "American" Christianity is in need of this deeper strain of expression of direct contact with God, as the source, not of world-flight, but of the most intensely "practical" Christianity that has yet been known.
from The Eternal Promise, reprinted in Quaker Spirituality: Selected Writings