There is no retracing our steps.
Multa ferunt anni venientes commoda secum, Multa recedentes adimiunt. (The years, as they come, bring many agreeable things with them; as they go, they take many away.)
Mediocrity is not allowed to poets, either by the gods or men.
Mountains will go into labour, and a silly little mouse will be born.
Drive Nature out with a pitchfork, yet she hurries back, And will burst through your foolish contempt, triumphant.
The work you are treating is one full of dangerous hazard, and you are treading over fires lurking beneath treacherous ashes.