So occupy yourself exclusively with the Hereafter

"Do not make your heart like a sponge soaking up any idea and specious arguments that come to mind, rather make it like a glass through whose surface the specious arguments pass but do not settle there, otherwise if all those doubts and specious arguments settle in your heart, it will be overwhelmed by them.” 

Shaykh al islam Ibn Taymiyyah



Doom comes about because of neglecting to evaluate one's self and because of just following one's whims.

Ibn Qayyim Al Jawziyyah

"So occupy yourself exclusively with the Hereafter, and empty your heart of all other thoughts; once you have done that, work hard! Do not waste time! And flee from the world and its temptations! Travel to the Hereafter (with your worship) before you are taken there… I have indeed given you the same advice that I gave myself" 

{Biography of Sufyaan ath Thawree, rahimahullaah}