Kullu nafsin tha-iqatu almawti wanablookum bishsharri walkhayri fitnatan wa-ilayna turjaAAoon (surah Anbiya: 35)

Tafseer Tafheem-ul-Quran by Syed Abu-al-A'la Maududi

(21:35) Every living being has to taste death, *37 and We are putting all of you to trial by passing you through good and bad conditions, *38 and ultimately you shall return to Us,

Kullu nafsin zaaa`iqatul mawt; wa nablookum bishsharri walkhairi fitnatanw wa ilainaa turja`oon

*37) This is a brief answer to all those warnings and curses with which the Holy Prophet was being threatened and the conspiracies which the Quraish were hatching against him day and night. On the one hand, the women of the Quraish cursed him because according to them he had ruined their home life by enticing away their kith and kits; while on the other, the chiefs of the Quraish threatened hits with horrible consequences for the propagation of Islam. After the emigration to Habash especially, which almost affected every home of Makkah, these curses and threats increased alI the more. This verse is meant to comfort and console the Holy Prophet as well so that he should continue his mission without any fear of their threats.
*38) That is, Allah is always putting human beings to test and trial both through adversity and affluence. This is to judge whether prosperity makes them proud, cruel and slaves of their lusts or they become grateful to Allah. On the other hand, He inflicts adversity upon them in order to see whether they remain within the prescribed and lawful limits or become low-spirited and down-hearted. A sensible person therefore should not be deluded by prosperity and adversity, but should keep their trial element in view and try to pass through it gracefully.