This difference he did not notice or value, until one day the eyes of
his soul were opened and he began to inquire the reason of the
difference. He learned by experience that one train of thought left
him sad, the other joyful. This was his first reasoning on spiritual
matters. Afterward, when he began the Spiritual Exercises, he was
enlightened, and understood what he afterward taught his children
about the discernment of spirits. When gradually he recognized the
different spirits by which he was moved, one, the spirit of God, the
other, the devil, and when he had gained no little spiritual light
from the reading of pious books, he began to think more seriously of
his past life, and how much penance he should do to expiate his past sins.