Surah Az-Zumar — Ayah 49 (39:49)
فَإِذَا مَسَّ ٱلۡإِنسَٰنَ ضُرّٞ دَعَانَا ثُمَّ إِذَا خَوَّلۡنَٰهُ نِعۡمَةٗ مِّنَّا قَالَ إِنَّمَآ أُوتِيتُهُۥ عَلَىٰ عِلۡمِۭۚ بَلۡ هِيَ فِتۡنَةٞ وَلَٰكِنَّ أَكۡثَرَهُمۡ لَا يَعۡلَمُونَ ٤٩
English translation (Saheeh International)
And when adversity touches man, he calls upon Us; then when We bestow on him a favor from Us, he says, "I have only been given it because of [my] knowledge." Rather, it is a trial, but most of them do not know.
Brief commentary
When a disbelieving man is afflicted by sickness, poverty etc. he calls out to Me to remove his affliction. Then when I bless him with health or wealth, the disbeliever says: Allah has only given me this because He knows that I deserve it. Actually it is a test and a means of luring him to his destruction. But most disbelievers do not know this and they are deceived by the blessings Allah gives them.