To know all things is not permitted.
Alas! the fleeting years, how they roll on!
Pale Death beats equally at the poor man's gate and at the palaces of kings.
The short span of life forbids us to spin out hope to any length. Soon will night be upon you, and the fabled Shades, and the shadowy Plutonian home.
If you drive nature out with a pitchfork, she will soon find a way back.
Consider well what your strength is equal to, and what exceeds your ability.