Surah Fussilat 41:50

وَلَئِنْ أَذَقْنَـٰهُ رَحْمَةً مِّنَّا مِنۢ بَعْدِ ضَرَّآءَ مَسَّتْهُ لَيَقُولَنَّ هَـٰذَا لِى وَمَآ أَظُنُّ ٱلسَّاعَةَ قَآئِمَةً وَلَئِن رُّجِعْتُ إِلَىٰ رَبِّىٓ إِنَّ لِى عِندَهُۥ لَلْحُسْنَىٰ ۚ فَلَنُنَبِّئَنَّ ٱلَّذِينَ كَفَرُوا۟ بِمَا عَمِلُوا۟ وَلَنُذِيقَنَّهُم مِّنْ عَذَابٍ غَلِيظٍ

And if We let him taste mercy from Us after an adversity which has touched him, he will surely say, "This is [due] to me, and I do not think the Hour will occur; and [even] if I should be returned to my Lord, indeed, for me there will be with Him the best." But We will surely inform those who disbelieved about what they did, and We will surely make them taste a massive punishment.

Translation: Saheeh International

Tafsir

And if wa-la-in the lām is for oaths We let him taste if We bestow on him mercy such as riches or good health from Us after the harm the hardship or tribulation that had befallen him he will surely say ‘This is my due! in other words it is on account of what I do. …

Excerpt from Tafsir al-Jalalayn, commentary on 41:50, via Quran.com. The reader has the full commentary and 9 more tafsirs.