What is the ruling on a person performing Hajj with money acquired from renting a commercial shop that is part of a dwelling he built with his salary and monetary gifts he received as a public sector employee, without coercion or abuse? And if that money is unlawful, what is the legitimate way to dispose of it?

A gift taken by an employee for performing his obligatory duty is a forbidden bribe. The recipient of it must repent to Allah and return the money to its owner if it enabled him to obtain his right. Otherwise, the money should be spent on the welfare of Muslims or given to the poor. If the bribe money was invested in something permissible, the resulting profits are lawful, and it is permissible to perform Hajj with them, although it is recommended for the pilgrim to ensure his earnings are of the purest kind.