A quote
Conduct will not be right unless the will to act is right; for this is the source of conduct. Nor, again, can the will be right without a right attitude of mind; for this is the source of the will. Furthermore, such an attitude of mind will not be found even in the best of men unless he has learned the laws of life as a whole and has worked out a proper judgment about everything, and unless he has reduced facts to a standard of truth. Peace of mind is enjoyed only by those who have attained a fixed and unchanging standard of judgment; the rest of mankind continually ebb and flow in their decisions, floating in a condition where they alternately reject things and seek them.
Seneca·Letter 95 — On the Usefulness of Basic Principles (§57)·trans. Gummere