Sura Āl-ʿImrān 3:139

وَلَا تَهِنُوا۟ وَلَا تَحْزَنُوا۟ وَأَنتُمُ ٱلْأَعْلَوْنَ إِن كُنتُم مُّؤْمِنِينَ

wa-lā tahinū wa-lā taḥzanū wa-antumu l-aʿlawna in kuntum muʾminīna

So lose not heart, nor fall into despair: For ye must gain mastery if ye are true in Faith.

Sura al-Nisāʾ 4:104

وَلَا تَهِنُوا۟ فِى ٱبْتِغَآءِ ٱلْقَوْمِ إِن تَكُونُوا۟ تَأْلَمُونَ فَإِنَّهُمْ يَأْلَمُونَ كَمَا تَأْلَمُونَ وَتَرْجُونَ مِنَ ٱللَّـهِ مَا لَا يَرْجُونَ وَكَانَ ٱللَّـهُ عَلِيمًا حَكِيمًا

wa-lā tahinū fī btighāi l-qawmi in takūnū talamūna fainnahum yalamūna ka-mā talamūna wa-tarjūna mina allāhi mā lā yarjūna wa-kāna allāhu ʿalīman ḥakīman

And slacken not in following up the enemy: If ye are suffering hardships, they are suffering similar hardships; but ye have Hope from Allah, while they have none. And Allah is full of knowledge and wisdom.

Sura Muḥammad 47:35

فَلَا تَهِنُوا۟ وَتَدْعُوٓا۟ إِلَى ٱلسَّلْمِ وَأَنتُمُ ٱلْأَعْلَوْنَ وَٱللَّـهُ مَعَكُمْ وَلَن يَتِرَكُمْ أَعْمَٰلَكُمْ

fa-lā tahinū wa-tadʿū ilā l-salmi wa-antumu l-aʿlawna wallāhu maʿakum wa-lan yatirakum aʿmālakum

Be not weary and faint-hearted, crying for peace, when ye should be uppermost: for Allah is with you, and will never put you in loss for your (good) deeds.