I'm currently reading The Imitation of Christ by Thomas a Kempis. Here are some of my favorite quotes so far:
"No man appears in safety before the public eye unless he first relishes obscurity. No man is safe in speaking unless he loves to be silent. No man rules safely unles he is willing to be ruled. No man commands safely unless he has learned well how to obey."
"Fight like a man. Habit is overcome by habit."
"Therefore, in every deed and every thought, act as though you were to die this very day. If you had a good conscience you would not fear death very much."
"The present is very precious; these are the days of salvation; now is the acceptable time."
"If your heart were right, then every created thing would be a mirror of life for you and a book of holy teaching, for there is no creature so small and worthless that it does not show forth the goodness of God."
"Why then, do you fear to take up the cross when through it you can win a kingdom?"