Muslim who dies and for whom a congregation of a hundred Muslims prays—it is also narrated as forty, and as three rows—interceding for him, without their intercession being accepted—or he said, ‘without his being forgiven.’” Allah Most High thus rewards the person who strives for his own striving, while showing mercy to the deceased through the efforts of this living person: his supplication for him, his charity on his behalf, his fasting on his behalf, and his pilgrimage on his behalf.

It is established in an authentic hadith that the Prophet (peace and blessings of Allah be upon him) said:

“There is no man who supplicates for his brother but Allah appoints an angel over him. Whenever he supplicates for his brother, the angel appointed over him says, ‘Amen, and may you be granted the same.’”

This is an example of the striving through which a believer benefits his brother: Allah rewards the one and shows mercy to the other.

“Man will have nothing except what he strives for.”

Not everything from which the deceased or the living benefits, or through which he receives mercy, is part of his own striving. Indeed, the children of believers enter Paradise with their parents without any striving of their own. Thus, what depends exclusively on one’s own striving is narrower in scope than benefit in general, so that a person should not seek reward for deeds other than his own. This is like a debt that someone pays on another’s behalf: the debtor is discharged from liability, but he does not own the funds with which the debt was paid. He should himself be the one to pay it. And Allah knows best.