Cicero, De Officiis
3.1.1 (tr. Walter Miller):
Cato, who was of about the same years, Marcus, my son, as that Publius Scipio who first bore the surname of Africanus, has given us the statement that Scipio used to say that he was never less idle than when he had nothing to do and never less lonely than when he was alone.
P. Scipionem, Marce fili, eum, qui primus Africanus appellatus est, dicere solitum scripsit Cato, qui fuit eius fere aequalis, numquam se minus otiosum esse, quam cum otiosus, nec minus solum, quam cum solus esset.