March 11th
Book Three, Chapter 33
Of the Inconstancy of our Heart, and of Directing our Final Intention to God

Trust not to your feeling; whatever it may be now it will be quickly changed into another.  As long as you live you are subject to change, even against your will....the purer the eye of your intention is, with so much greater constancy will you pass through these diverse storms.  But in many the eye of pure intention is dark; for men quickly look towards something delightful as it comes in their way; and seldom will you find any one altogether free from all blemish of self-seeking.