One of the ways to obtain the quality of euthymia, “tranquillity [of mind], says Seneca (ca. 4 B.C. to 65 A.D.), is to practice thrift in all things:
Let us get used to banishing ostentation, and to measuring things by their qualities of function rather than display…Let us learn to increase our self-restraint, to curb luxury, to moderate ambition, to soften anger, to regard poverty without prejudice, to practise frugality, even if many are ashamed of it, to apply to nature’s needs the remedies that are cheaply available, to curb as if in fetters unbridled hopes and a mind obsessed with the future, and to aim to acquire our riches from ourselves rather than from Fortune. It is not possible that all the manifold and unfair disasters of life can be so repelled that many storm winds will not still assail those who spread their sails ambitiously. We must restrict our activities so that Fortune’s weapons miss their mark; and for that reason exiles and calamities have proven to benefit us and greater disasters have been mended by lesser ones. When the mind is less amenable to instruction and cannot be cured by milder means, why should it not be helped by having a dose of poverty and disgrace and general ruin – dealing with evil by evil? So let us get used to dining without a mass of people, to being slave to fewer slaves, to acquiring clothes for their proper purpose, and to living in more restricted quarters. Not only in running and the contests of the Circus, but in this race course of our lives we must keep to the inner track. - “On Tranquillity of Mind,” in Seneca: Dialogues and Letters, ed. and trans. C.D.N. Costa (New York: Penguin Classics, rep. 2005), pp. 44-45
Considering that these thoughts are part of a meditation on the evils which having too much money and too many material possessions bring a man, it’s interesting that a few of Seneca’s sentences echo New Testament ethics. Self-restraint is a fruit of the Spirit (Gal. 5:23), the love of money which is the root of all evil (1 Tim. 6:7), we are to take no thought for tomorrow since each day has enough trouble of its own (Mt. 6:34), and if we have food and clothing we are to be content (1 Tim. 6:8). Though we don’t believe in the goddess Dame Fortune and don’t think that our external righteousness merits us anything with God, we Christians, too, are in some very important ways supposed to “keep to the inner track.” Seneca and Paul can agree on that much.