Saying one thing while meaning another, often the opposite. The true sense is left to whoever reads or hears.
In Paradise
if your fingers are not enough for such a knot, it is no wonder: from so much not trying it, it has grown hard!
Beatrice speaks as if she lamented the lack of strength in Dante's fingers, but she means that he never tried. The grace lies in what remains underneath: the reproach comes as a joke, and the student understands the invitation to try.
Cantos XXV to XXVIII: The three virtues and the Primum Mobile, Beatrice, to Dante, in Canto XXVIII