What is the difference between "strength of soul" and "strength of character?"
Strength of character is the pride of morality and humanity. Strength of soul is the pride of Spirituality, Eternity and Infinity. Having said this, I do not want to leave you with the impression that morality has no value in the inner and spiritual life. On the contrary, a solid morality is preparatory to a deep spirituality. Strength of soul is the inner power or certitude that comes from the Divine within you. When you have seen your soul, you have felt God's Will within you and you have been given the strength to manifest His Will here on earth.
Sri Chinmoy, Yoga and the spiritual life. The journey of India's Soul., Tower Publications, Inc., New York, 1971