يَوْمَ تُبْلَى السَّرَائِرُ

This verse refers to the Day of Judgment when all hidden matters will be exposed and examined. The word "sara'ir" refers to secrets, hidden thoughts, intentions, and concealed actions that were known only to Allah in worldly life. On that Day, nothing will remain hidden - all the secrets of the heart, private actions, and concealed intentions will be brought to light and tested. This serves as both a warning and a motivation: a warning to those who hide evil deeds or harbor bad intentions, and motivation for those who do good in secret, knowing that their hidden righteousness will be revealed and rewarded. The verse encourages sincerity in all actions and thoughts, knowing that ultimate accountability includes even the most private aspects of human behavior.