In Surah Al-Kahf, Allah describes the real losers in a powerful ayah:

“Say, [O Muhammad], shall We inform you of the greatest losers as to [their] deeds? They are those whose efforts in the worldly life were misguided while they thought they were doing good.” 

(Surah Al-Kahf, 18:103–104)

This ayah serves as a sobering reminder that true loss is not just failure in this world, but striving hard in life with sincerity yet without proper guidance. These are people who may appear successful outwardly, yet their actions lack alignment with divine truth. It teaches us the importance of intention, sincerity, and ensuring our deeds are rooted in the guidance of Allah and His Messenger ﷺ. Without this, even the most dedicated efforts can ultimately be in vain.