‘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 who is lost or gone away. It cannot resurrect the dead, it cannot change fate, it can bring no benefit whatsoever.
Do not be sad, because sadness is often from the devil and is a kind of hopelessness.”
(pg 155-156, ‘Don’t Be Sad’ by ‘Aaidh ibn Abdullah al-Qarni)