Do not be anxious about tomorrow, for tomorrow will be anxious for itself. Let the day's own trouble be sufficient for the day
Tomorrow every fault is to be amended; but tomorrow never comes
One today is worth two tomorrows
Catch the opportunity while it lasts, and rely not on what tomorrow may bring
Refrain from asking what going to happen tomorrow, and everyday that fortune grants you, count as gain


On Anger: "For every minute you remain angry, you give up sixty seconds of peace of mind."
On Destiny: "Our destiny exercises its influence over us even when, as yet, we have not learned its nature: it is our future that lays down the law of our today."
Human, All Too Human
On Friendship: "A crowd is not company; and faces are but a gallery of pictures; and talk but a tinkling cymbal, where there is no love."