13 And that you may learn that not from the difficulty of the thing, but through our inattention, this sin has advanced to such a pitch, let us call to mind how many things far more difficult than these, men accomplish; and that too without expecting any recompense therefrom. Let us think what services the Devil imposes; how laborious, how troublesome they are; and yet, the difficulty has not become an obstacle to these services. For what can be more difficult, I ask, than when any young person delivering himself up to those, who undertake to make his limbs supple and pliant, uses his most strenuous exertion to bend his whole body into the exact shape of a wheel, and to turn over upon the pavement; his powers being tasked at the same time through the eyes, and through the movement of the hands, as well as other convolutions for the purpose of being transformed into the likeness of woman-kind. Yet neither the difficulty of these feats, nor the degradation arising from them, are thought of.
And again, those who are dragged upon the dancing-stage, and use the members of the body as though they were wings, who that beholds them can help being struck with wonder? So too they who toss knives aloft in the air one after another, and catch them all by the handle, whom might they not put to shame of those who refuse to undergo any labour for the sake of virtue? And what can any one say of those men, who balancing a pole on the forehead, keep it just as steady as a tree rooted in the ground?
And this is not the only marvellous part of the affair but that they set little children to wrestle with one another on the top of the tree; and neither the hands, nor any other part of the body assisting, the forehead alone sustains the pole unshaken, and with more steadiness than any kind of fastening. Again: another walks on the slenderest rope, with the same fearlessness as men do when they run over level plains. Nevertheless these things, which even in thought seem impracticable, have become possible by art. What like this have we, I ask, to allege concerning oaths? What kind of difficulty? What toil? What art? What danger? There is only needed on our part a little earnestness, and the whole of our task will be quickly performed.
Source: Homilies on the Statues (New Advent)