By being sad, you give pleasure to your adversary, which is why our religion commands us to instill awe into the hearts of the enemy.
(…to threaten the enemy of Allah and your enemy….) (Qur’an 8: 60)
On the day of Uhud, when Abu Dujanah (may Allah be pleased with him) was prancing between the rows of the Muslim army, the Prophet (bpuh) said:
“Verily, it is a way of walking that Allah hates, except in this situation."
And when the disbelievers were observing the Muslims from hilltops, the Prophet (bpuh) ordered the Companions to jog around the Ka’bah in order to display their strength and endurance.
(And on that Day, the believers [i.e. Muslims] will rejoice [at the victory given by Allah to the Romans against the Persians].) (Qur’an 30: 4)
The enemies of the truth feel pain when they find out that we are happy or joyful.
(Say: ‘Perish in your rage.) (Qur’an 3: 119)
(If good befalls you [O’ Muhammad], it grieves them….)
(Qur’an 9: 50)
(They desire to harm you severely.) (Qur’an 3: 118)
The Prophet (bpuh) said:
"O’ Allah, Don’t allow the enemy or the jealous one to rejoice at my misfortune?
An Arab poet said:
"A young man can forbear every kind of misfortune, Except for the enemy’s joy in his affliction”
Our pious Muslim predecessors would smile, be patient, and display tolerance in the face of hardship, in order to thwart the jealous one and the one who gloats over another’s grief
(But they never lost heart for that which did befall them in Allah s Way, nor did they weaken nor degrade themselves.) (Qur’an 3: 146)