If you know these things, happy are ye if ye do them.
                                              - John xiii. 17

Therefore to him that knoweth to do good, and doeth it not, to him it is sin.
                                            - James iv. 17

          We cannot kindle when we will
              The fire that in the heart resides,
          The spirit bloweth and is still,
              In mystery our soul abides:
          But tasks in hours of insight willed
          Can be through hours of gloom fulfilled.
                                            Matthew Arnold

HURT not your conscience with any known sin.
                                            S. Rutherford

DEEP-ROOTED customs, though wrong, are not easily altered; but it is the duly of all to be firm in that which they certainly know is right for them.                     
                                            John Woolman

HE often acts unjustly who does not do a certain thing; not only he who does a certain thing.
                                            Marcus Antonius

EVERY duty we omit obscures some truth we should have known.
                                            John Ruskin