Do not be sad, because sadness causes you to regret the past, to have misgivings concerning the future, and to make you waste away your present.
Do not be sad, because it causes the heart to contract, the face to frown, the spirit to weaken, and hope to vanish.
Do not be sad, because your sadness pleases your enemy, angers your friend, and makes the jealous rejoice.
Do not be sad, because by being sad, you are complaining against the divine decree and showing vexation at what is written for you.
Do not be sad, because grief cannot return to you the one that is lost or is gone away. lt cannot resurrect the dead, it cannot change fate, or bring any benefit whatsoever.
Do not be sad, because sadness is often from the devil and is a kind of hopelessness.
(Have we not opened your breast for you [O’ Muhammad]? And removed from you your burden, which weighed down on your back? And raised high your fame? So verily, with the hardship, there is relief verily with the hardship, there is relief [i.e. there is one hardship with two reliefs, .so one hardship cannot overcome two reliefs]. So when you have finished [from your occupation], then stand up for Allah is worship [i.e. stand up for prayer]. And to your Lord [Alone] turn [all your intentions and hopes and] your invocations.) (Qur’an 94: l-8)