Sura al-Baqara 2:260

وَإِذْ قَالَ إِبْرَٰهِـۧمُ رَبِّ أَرِنِى كَيْفَ تُحْىِ ٱلْمَوْتَىٰ قَالَ أَوَلَمْ تُؤْمِن قَالَ بَلَىٰ وَلَٰكِن لِّيَطْمَئِنَّ قَلْبِى قَالَ فَخُذْ أَرْبَعَةً مِّنَ ٱلطَّيْرِ فَصُرْهُنَّ إِلَيْكَ ثُمَّ ٱجْعَلْ عَلَىٰ كُلِّ جَبَلٍ مِّنْهُنَّ جُزْءًا ثُمَّ ٱدْعُهُنَّ يَأْتِينَكَ سَعْيًا وَٱعْلَمْ أَنَّ ٱللَّـهَ عَزِيزٌ حَكِيمٌ

wa-idh qalā ibrāhīmu rabbi arinī kayfa tuḥyi l-mawtā qalā a-wa-lam tuʾmin qalā balā wa-lākin li-yaṭmaʾinna qalbī qalā fa-khudh arbaʿatan mina l-ṭayri fa-ṣurhunna ilayka thumma ajʿal ʿalā kulli jabalin minhunna juzʾan thumma udʿuhunna yaʾtīnaka saʿyan wa-aʿlam annā allāha ʿazīzun ḥakīmun

When Abraham said: "Show me, Lord, how You will raise the dead, " He replied: "Have you no faith?" He said "Yes, but just to reassure my heart." Allah said, "Take four birds, draw them to you, and cut their bodies to pieces. Scatter them over the mountain-tops, then call them back. They will come swiftly to you. Know that Allah is Mighty, Wise."

Sura Āl-ʿImrān 3:126

وَمَا جَعَلَهُ ٱللَّـهُ إِلَّا بُشْرَىٰ لَكُمْ وَلِتَطْمَئِنَّ قُلُوبُكُم بِهِۦ وَمَا ٱلنَّصْرُ إِلَّا مِنْ عِندِ ٱللَّـهِ ٱلْعَزِيزِ ٱلْحَكِيمِ

wa-mā jaʿalahu allāhu illā bushra la-kum wa-li-taṭmaʾinna qulūbukum bihi wa-mā l-naṣru illā min ʿindi allāhi l-ʿazīzi l-ḥakīmi

Allah made it but a message of hope for you, and an assurance to your hearts: (in any case) there is no help except from Allah. The Exalted, the Wise:

Sura al-Māʾidah 5:113

قَالُوا۟ نُرِيدُ أَن نَّأْكُلَ مِنْهَا وَتَطْمَئِنَّ قُلُوبُنَا وَنَعْلَمَ أَن قَدْ صَدَقْتَنَا وَنَكُونَ عَلَيْهَا مِنَ ٱلشَّٰهِدِينَ

qālū nurīdu an nnakula minhā wa-taṭmaʾinna qulūbunā wa-naʿlama an qad ṣadaqtanā wa-nakūna ʿalayhā mina l-shāhidīna

They said: "We only wish to eat thereof and satisfy our hearts, and to know that thou hast indeed told us the truth; and that we ourselves may be witnesses to the miracle."

Sura al-Anfāl 8:10

وَمَا جَعَلَهُ ٱللَّـهُ إِلَّا بُشْرَىٰ وَلِتَطْمَئِنَّ بِهِۦ قُلُوبُكُمْ وَمَا ٱلنَّصْرُ إِلَّا مِنْ عِندِ ٱللَّـهِ إِنَّ ٱللَّـهَ عَزِيزٌ حَكِيمٌ

wa-mā jaʿalahu allāhu illā bushra wa-li-taṭmaʾinna bihi qulūbukum wa-mā l-naṣru illā min ʿindi allāhi inna allāha ʿazīzun ḥakīmun

Allah made it but a message of hope, and an assurance to your hearts: (in any case) there is no help except from Allah: and Allah is Exalted in Power, Wise.

Sura Yūnus 10:7

إِنَّ ٱلَّذِينَ لَا يَرْجُونَ لِقَآءَنَا وَرَضُوا۟ بِٱلْحَيَوٰةِ ٱلدُّنْيَا وَٱطْمَأَنُّوا۟ بِهَا وَٱلَّذِينَ هُمْ عَنْ ءَايَٰتِنَا غَٰفِلُونَ

inna lladhīna lā yarjūna liqāʾanā wa-raḍū bil-ḥayawāt l-dunyā wa-iṭmaʾannū bihā wa-lladhīna hum ʿan āyātinā ghāfilūna

Those who rest not their hope on their meeting with Us, but are pleased and satisfied with the life of the present, and those who heed not Our Signs,-

Sura al-Raʿd 13:28

ٱلَّذِينَ ءَامَنُوا۟ وَتَطْمَئِنُّ قُلُوبُهُم بِذِكْرِ ٱللَّـهِ أَلَا بِذِكْرِ ٱللَّـهِ تَطْمَئِنُّ ٱلْقُلُوبُ

lladhīna āmanū wa-taṭmaʾinnu qulūbuhum bi-dhikri allāhi āla bi-dhikri allāhi taṭmaʾinnu l-qulūbu

"Those who believe, and whose hearts find satisfaction in the remembrance of Allah: for without doubt in the remembrance of Allah do hearts find satisfaction.

Sura al-Ḥajj 22:11

وَمِنَ ٱلنَّاسِ مَن يَعْبُدُ ٱللَّـهَ عَلَىٰ حَرْفٍ فَإِنْ أَصَابَهُۥ خَيْرٌ ٱطْمَأَنَّ بِهِۦ وَإِنْ أَصَابَتْهُ فِتْنَةٌ ٱنقَلَبَ عَلَىٰ وَجْهِهِۦ خَسِرَ ٱلدُّنْيَا وَٱلْأَخِرَةَ ذَٰلِكَ هُوَ ٱلْخُسْرَانُ ٱلْمُبِينُ

wa-mina l-nāsi man yaʿbudu allāha ʿalā ḥarfin fa-in aṣābahu khayrun iṭmaʾanna bihi wa-in aṣābathu fitnatun inqalaba ʿalā wajhihi khasira l-dunyā wa-l-akhirata dhālika huwa l-khusrānu l-mubīnu

There are among men some who serve Allah, as it were, on the verge: if good befalls them, they are, therewith, well content; but if a trial comes to them, they turn on their faces: they lose both this world and the Hereafter: that is loss for all to see!