Facilis descensus Averno Noctes atque dies patet atri ianua Ditis; Sed revocare gradum superasque evadere ad auras, Hoc opus, hic labor est.
The gates of hell are open night and day; Smooth the descent, and easy is the way: But to return, and view the cheerful skies, In this the task and mighty labor lies.
It is easy to go down into Hell; Night and day, the gates of dark Death stand wide; But to climb back again, to retrace one's steps to the upper air— There's the rub, the task.
Compare:
Long is the way And hard, that out of Hell leads up to Light.