Pliny the Younger, Letters
3.1.2 (to Calvisius Rufus; tr. Betty Radice):
A well-ordered life, especially where the old are concerned, gives me the same pleasure as the fixed course of the planets. A certain amount of irregularity and excitement is not unsuitable for the young, but their elders should lead a quiet and orderly existence; their time of public activity is over, and ambition only brings them into disrepute.
Me autem ut certus siderum cursus ita vita hominum disposita delectat. Senum praesertim: nam iuvenes confusa adhuc quaedam et quasi turbata non indecent, senibus placida omnia et ordinata conveniunt, quibus industria sera turpis ambitio est.