The Quran in some verses uses the word Khusran, which means losing oneself. One can live in this world and own many things but lose himself. God says in Verse 15 of Surah Az-Zumar: “Worship besides Him whatever you want. The greatest losers are those whose souls and family members will be lost on the Day of Judgment for this is certainly a great loss.”
The word Khusr in Arabic refers to deficiency in one’s main capital. According to Allameh Tabatabaei, Khusr and Khusran both mean losing one’s capital and Khusran Nafs is when one pit himself in a situation that he loses himself and the capacity to reach perfection and salvation. And this is the true loss whose outcomes are forever.
This verse can show the effects of faith in improvement of one’s relations with oneself. It can be said that when someone establishes a relation with God, a seed is planted in him which grows gradually and he will see its fruits.
Although interpreters say the verse is about disbelievers, it is clear that all people are exposed to losses, as the Quran says in Surah Al-Asr (Verse 2): “Surely, the human is in a (state of) loss.”
The ways for getting away from loss have also been clearly mentioned in Surah Al-Asr: “Except those who believe and do good works and charge one another with the truth and charge one another with patience.” (Verse 3)
So the best way for staying away from loss in having such a faith in God that will help him see everything in this world as a sign of God and teach him things of which he has no knowledge: “(will) give you wisdom and instruct you in that which you did not know.” (Surah Al-Baqarah, Verse 151)