Sayings of the Salaf

"I have known people and kept company with groups who neither rejoiced when the things of this
 world came to them, nor grieved when they lost anything in this world. The life of this world was
 more insignificant to them than dust. One of them might live for a year or for sixty years without
ever having a garment that would entirely cover him, and without ever having anything that would
 come between him and the ground, and without ever having any food that he could ask to be prepared
for him in his own home. When night came, they would be on their feet, with their foreheads flat against
 the earth, tears rolling down their cheeks, secretly calling on Allah to save them on the Day of Judgement.
 If they did something good, they never stopped being grateful for it, and they were always asking Allah to
 forgive them for it. By Allah, they were not safe from wrong actions, and were saved only by their constant
turning in repentance. May Allah be pleased with them and grant them His mercy." Al-Hasan Al-Basri

"I have seen wrong actions killing hearts, and their degradation may lead to their becoming addicted to
 them. Turning away from wrong actions gives life to the hearts, and opposing yourself is best for it."
 Abdullaah Ibn Al-Mubarak

"Be content with what you have, be satisfied with your dwelling place to accommodate your enterprise,
restrain your tongue, and shed tears of regret regarding past sins you committed knowingly, and those
you do not recognize." Abdullaah bin Mas'ood

"One's heart sometimes feels a strong yearning and responsiveness, and yet, at other times, it feels
waning and disengaged. Take advantage of its responsiveness when inviting, and disregard what is
offered when your heart feels despondent." Abdullaah bin Mas'ood