Our search for such [moral] principles can start with . . . the unconditional imperative to acknowledge every person as a person. If we ask for the contents given by this absolute, we find, first, something negative-the command not to treat a person as a thing. This seems little, but it is much. It is the core of the principle of justice.

Courage is a greater virtue than love. At best, it takes courage to love.

In those who rest on their unshakable faith, pharisaism and fanaticism are the unmistakable symptoms of doubt which has been repressed. Doubt is not overcome by repression but by courage. Courage does not deny that there is doubt, but it takes the doubt into itself as an expression of its own finitude and affirms the content of an ultimate concern. Courage does not need the safety of an unquestionable conviction. It includes the risk without which no creative life is possible.

The awareness of the ambiguity of one's highest achievements, as well as one's deepest failures is a definite symptom of maturity.

Knowledge of that which concerns us infinitely is possible only in an attitude of infinite concern.

Doubt is the necessary tool of knowledge.

The separation of faith and love is always a consequence of a deterioration of religion.