Suetonius, Divus Augustus (25):
Augustus thought that nothing was less appropriate to the perfect general than haste and temerity. He used all the time to toss about the saying,
Hasten slowly: a sure commander is better than a bold one.
And,
Whatever turns out well has been effected swiftly enough.
He also used to deny that one should ever undertake a battle or a war, except when greater hope of emolument than fear of loss was on offer. For, he used to say that those who pursued the slightest advantages at something more than the slightest risk were similar to those who went fishing with golden hooks, the loss of which could not be compensated for by any catch.
Nihil autem minus perfecto duci quam festinationem temeritatemque convenire arbitrabatur. Crebro itaque illa iactabat:
Σπευδε βραδέως. ἀσφαλὴς γάρ ἐστ’ ἀμείνων ἢ θρασὺς στρατηλάτης
Et: sat celeriter fieri quidquid fiat satis bene. Proelium quidem aut bellum suscipiendum omnino negabat, nisi cum maior emolumenti spes quam damni metus ostenderetur. Nam minima commoda non minimo sectantis discrimine similes aiebat esse aureo hamo piscantibus, cuius abrupti damnum nulla captura pensari posset.
