Herbert Spencer

The truly honest man here and there to be found, is not only without thought of legal, religious, or social compulsion, when he discharges an equitable claim on him; but he is without thought of self-compulsion. He does the right thing with a simple feeling of satisfaction in doing it; and is, indeed, impatient if anything prevents him from having the satisfaction of doing it.

Herbert Spencer, The Data of Ethics (1879), Ch. 7, “The Psychological View.”