Self-Sufficiency

Epictetus, Enchiridion (XLVIII) in The Works of Epictetus, tr. Thomas Wentworth Higginson (New York: Thomas Nelson and Sons, 1890), p. 220:

The condition and characteristic of a vulgar person is that he never looks for either help or harm from himself, but only from externals. The condition and characteristic of a philosopher is that he looks to himself for all help or harm.