“Needs must it be hard, since it is so seldom found. How would it be possible, if salvation were ready to our hand, and could without great labour be found, that it should be by almost all men neglected? But all things excellent are as difficult as they are rare.”
Et sane arduum debet esse, quod adeo raro reperitur. Qui enim posset fieri, si salus in promptu esset et sine magno labore reperiri posset, ut ab omnibus fere negligeretur? Sed omnia praeclara tam difficilia, quam rara sunt.
Part V, Prop. XLII, Scholium
Ethics (1677)