Go with your fate, but not beyond. Beyond leads to dark places. Mary Renault
A world full of happiness is not beyond human power to create; the obstacles imposed by inanimate nature are not insuperable. The real obstacles lie in the heart of man, and the cure for these is a firm hope, informed and fortified by thought. Bertrand Russell
But the best demonstration by far is experience, if it go not beyond the actual experiment. Francis Bacon
What song the Syrens sang, or what name Achilles assumed when he hid himself among women, though puzzling questions, are not beyond all conjecture. Thomas Browne
Step not beyond the beam of the balance. Pythagoras
Live not beyond your means. Latin Proverb