The mistake made by all previous systems of ethics has been the failure to recognize that life as such is the mysterious value with which they have to deal. All spiritual life meets us within natural life. Reverence for life, therefore, is applied to natural life and spiritual life alike. In the parable of Jesus, the shepherd saves not merely the soul of the lost sheep but the whole animal. The stronger the reverence for natural life, the stronger grows also that for spiritual life.

The Spiritual Life (1947)