There is no joy for the one who does not bear sadness, there is no sweetness for the one who does not have patience, there is no delight for the one who does not suffer, and there is no relaxation for the one who does not endure fatigue.
Ibn Qayyim Al-JawziyyaHad Allah lifted the veil for his slave and shown him how He handles his affairs for him, and how Allah is more keen for the benefit of the slave than his own self, his heart would have melted out of the love for Allah and would have been torn to pieces out of thankfulness to Allah. Therefore if the pains of this world tire you, do not grieve. For it may be that Allah wishes to hear your voice by way of Dua'a. So pour out your desires in prostration and forget about it and know; that verily Allah does not forget it.
Ibn Qayyim Al-JawziyyaRepel the thought, for if you don't, it becomes an idea. So repel the idea, for if you don't it will become a desire. So fight against that(desire), for if you don't, it will become a determination and a passion. And if you don't repel that, it will become an action. And if you don't replace it with its opposite, it will become a constant habit. So at that point, it will be difficult for you to change it.
Ibn Qayyim Al-Jawziyya