Out of adversity

Genuine morality is preserved only in the school of adversity; a state of continuous prosperity may easily prove a quicksand of virtue. - Johann Schiller

Adversity makes men; good fortune makes monsters. - French Proverb

The gem cannot be polished without friction, nor man perfected without trials. - Chinese Proverb

On Accomplishment

Have a time and place for everything, and do everything in its time and place, and you will not only accomplish more but have far more leisure than those who are always hurrying, as if vainly attempting to overtake time that had been lost. - Tyron Edwards 

He who considers too much will perform little. - Johann Schiller

Knowledge and courage take turns at greatness. - Baltasar Gracian

We never seem to have enough

Patience is the companion of wisdom. - St. Augustine

Patience strengthens the spirit, sweetens the temper, stifles anger, extinguishes envy, subdues pride, bridles the tongue. - George Horne

Only those who have the patience to do simple things perfectly will acquire the skill to do difficult things easily. - Johann Friedrich von Schiller