Betwixt the devil and the deep sea.
Erasmus, Adagia, Chapter III. Cent, IV. 94. Quoted from the Greek. Proverb in Hazlitt, English Proverbs. Clarke, Parœmiologia (1639). Said by Col. Monroe, Expedition and Observations, Part III, p. 55. (Ed. 1637).
Bona prudentiæ pars est nosse stultas vulgi cupiditates, et absurdas opiniones.Erasmus
You must acquire the best knowledge first, and without delay; it is the height of madness to learn what you will later have to unlearn.Erasmus