Is it permissible for a son to perform the obligatory Hajj on behalf of his deceased parents, and will the reward accrue to them as if they had performed it themselves, such that their past sins are forgiven?

Hajj on behalf of deceased parents is of two types:

1. If they passed away after Hajj became obligatory upon them, but they did not perform it despite the availability of conditions and they left behind wealth: Hajj must be performed on their behalf from their wealth, due to the Prophet's (peace be upon him) saying: "The debt owed to Allah is more deserving of being fulfilled."

2. If Hajj was not obligatory upon them due to the unavailability of conditions: It is commendable for the son to perform Hajj on their behalf, because the Prophet (peace be upon him) commanded Abu Razin to do so, saying: "Perform Hajj and Umrah on behalf of your father." It is commendable to start with the mother.

Hajj on behalf of parents is accepted and everyone involved is rewarded for it, as stated in the Hadith: "If a man performs Hajj on behalf of his parents, it is accepted from him and from them, and their souls rejoice in the heavens, and it is recorded with Allah as an act of righteousness." This reward does not reach the level of their performing Hajj for themselves, because the reward is commensurate with the difficulty.