Letters 50.9

But although virtues, when admitted, cannot depart and are easy to guard, yet the first steps in the approach to them are toilsome, because it is characteristic of a weak and diseased mind to fear that which is unfamiliar. The mind must, therefore, be forced to make a beginning; from then on, the medicine is not bitter; for just as soon as it is curing us it begins to give pleasure. One enjoys other cures only after health is restored, but a draught of philosophy is at the same moment wholesome and pleasant. Farewell.

Seneca, Letters to Lucilius 50.9, translated by Richard Mott Gummere