ΣΠΕΥΔΕ βραδέως, i.e. festina lente, “Make haste slowly.” This charming proverb appears at first glance a riddle, because it is made up of words which contradict each other. It is therefore to be classed with those which express their meaning through ἐναντίωσιν, that is, contrariety, as we explained in the beginning of the Adages. Of this genus is the saying δυσδαίμων εὐδαιμονία, unfortunate good fortune. Nor does it seem a groundless conjecture that our present proverb was created from a phrase which appears in Aristophanes’ Knights: σπεῦδε ταχέως, hasten hastily, so that the person who made the allusion, whoever he was, converted the ἀναδίπλωσιν, or doubling, into contrariety, ἐναντίωσιν The apt and absolute brevity of the phrase gives a superlative grace to the rhetorical figuration and to the humor of the allusion, a gem-like grace that seems to me to be especially beautiful in proverbs, and to make them gem-like marvels of price.

from Erasmus: 'Festina Lente' - Adagia II, 1, 1.