Aeneas and the Sybil of Cumae: Invia virtuti nulla est via.

He entered the cave of the Sibyl, and asked to go down to Avernus, to find his father’s ghost. Then the Sibyl after remaining, for a long time, with her eyes gazing at the earth, lifted them, at last, filled with the frenzy of the god, and cried: ‘You ask great things, man of great achievements, whose hand has been tested by the sword, whose faith has been tested by the fire. But have no fear, Trojan, you will have what you desire, and, with me as your guide, you will know the halls of Elysium, and earth’s strangest realm, and the likeness of your dear father. To virtue, no way is barred.’

Ovid, Metamorphoses Book XIV, 153.