Letter 71 — On the Supreme Good (§28)

“And so when one has just begun, or is on one’s way to the heights and is cultivating virtue, or even if one is drawing near the perfect good but has not yet put the finishing touch upon it, one will retrograde at times and there will be a certain slackening of mental effort. For such a man has not yet traversed the doubtful ground; he is still standing in slippery places.”