How charming is divine philosophy!
  Not harsh, and crabbed, as full fools suppose,
    But musical as is Apollo's lute...

                Milton, Mask of Comus (l. 476)

Dionysius the Pseudo-Areopagite
St John of the Cross
Walter Hilton
Richard Rolle
Thomas a Kempis
Jacob Boehme
Nicholas of Cusa

Paul Tillich
Soren Kierkegaard
Thomas Merton
Henri Nouwen

Paul Tillich

"The courage to be is the courage to accept oneself as accepted in spite of being unacceptable"

"Existence is estrangement and not reconciliation; it is dehumanization and not the expression of essential humanity...man becomes a thing and ceases to be a person. History is not the divine self-manifestation but a series of unreconciled conflicts, threatening humanity with self-destruction. The existence of the individual is filled with anxiety and threatened by meaninglessness" Systematic TheologyVolume II, p25.