Whatever you would make habitual, practice it; and if you would not make a thing habitual, do not practice it, but accustom yourself to something else.
καθόλου οὖν εἴ τι ποιεῖν ἐθέλῃς, ἑκτικὸν ποίει αὐτό· εἴ τι μὴ ποιεῖν ἐθέλῃς, μὴ ποίει αὐτό, ἀλλ᾿ ἔθισον ἄλλο τι πράττειν μᾶλλον ἀντ᾿ αὐτοῦ.
Original text (Ancient Greek)