Key Verses

1. 12:87Yusuf
   يَٰبَنِيَّ ٱذۡهَبُواْ فَتَحَسَّسُواْ مِن يُوسُفَ وَأَخِيهِ وَلَا تَاْيۡـَٔسُواْ مِن رَّوۡحِ ٱللَّهِۖ إِنَّهُۥ لَا يَاْيۡـَٔسُ مِن رَّوۡحِ ٱللَّهِ إِلَّا ٱلۡقَوۡمُ ٱلۡكَٰفِرُونَ
   Go, O my sons, and ascertain concerning Joseph and his brother, and despair not of the Spirit of Allah. Lo! none despaireth of the Spirit of Allah save disbelieving folk.
   In context

   Their father told them to go and find out news about Joseph and his brother, and not to despair of relief from Allah and His release of His servants. Without doubt, only disbelieving people despair of relief from Allah and His release of His servants, because they do not know the greatness of Allah’s power and His subtle favour upon His servants.

2. 15:56Al-Hijr
   قَالَ وَمَن يَقۡنَطُ مِن رَّحۡمَةِ رَبِّهِۦٓ إِلَّا ٱلضَّآلُّونَ
   He said: And who despaireth of the mercy of his Lord save those who are astray?
   In context

   Abraham said: Does anyone despair from the mercy of his Lord but those who have deviated from Allah’s straight path?!

3. 39:53Az-Zumar
   ۞قُلۡ يَٰعِبَادِيَ ٱلَّذِينَ أَسۡرَفُواْ عَلَىٰٓ أَنفُسِهِمۡ لَا تَقۡنَطُواْ مِن رَّحۡمَةِ ٱللَّهِۚ إِنَّ ٱللَّهَ يَغۡفِرُ ٱلذُّنُوبَ جَمِيعًاۚ إِنَّهُۥ هُوَ ٱلۡغَفُورُ ٱلرَّحِيمُ
   Say: O My slaves who have been prodigal to their own hurt! Despair not of the mercy of Allah, Who forgiveth all sins. Lo! He is the Forgiving, the Merciful.
   In context

   Say - O Messenger, to My servants who have gone beyond the limit against themselves by ascribing partners to Allah and committing sins: Do not lose hope of Allah’s mercy and of His forgiveness for your sins. Allah forgives all the sins of those who repent to Him. He is the Forgiving towards the sins of those who repent and the Merciful towards them.

4. 41:49Fussilat
   لَّا يَسۡـَٔمُ ٱلۡإِنسَٰنُ مِن دُعَآءِ ٱلۡخَيۡرِ وَإِن مَّسَّهُ ٱلشَّرُّ فَيَـُٔوسٞ قَنُوطٞ
   Man tireth not of praying for good, and if ill toucheth him, then he is disheartened, desperate.
   In context

   Man does not tire of asking for health, wealth, children and other favours. If he is afflicted by poverty, sickness and the like then he becomes extremely despondent of Allah’s mercy.