The only person who is really an atheist is one who denies that there is any reality that sustains meaning and goodness in the human venture. The true atheist is one who recognizes nothing as validly commanding. It is very difficult to find this sort of atheist, perhaps impossible.

"A Faith for the Free", in Together we advance, ed. Stephen H. Fritchman (Beacon: Boston 1946); in The prophethood of all believers, edited by George K. Beach (Beacon: Boston 1986) p 50

Atheism and prophecy

An authentic prophet is one who prophesies in fashion that does not comfort people, but actually calls them to make some new sacrifices. That's an authentic prophet, whether one speaks in the name of God or whatever. A great deal of authentic prophetism in the modern world is to be found in nonreligious terms and in nonchurch configurations, often even hostile to the church. The churches themselves have broadly failed in the prophetic function. Therefore a good deal of so-called atheism is itself, from my point of view, theologically significant. It is the working of God in history, and judgement upon the pious. An authentic prophet can and should be a radical critic of spurious piety, of sham spirituality.

"Prophetic judgment and grace," responses to questions, january 1977
in The prophethood of all believers, edited by George K. Beach (Beacon: Boston 1986) p 57