Is it permissible for a person who has retired early and receives a pension to take on a new job and earn an additional salary without the knowledge of the Social Insurance Agency, in order to improve his income, knowing that some consider this forbidden and that the Social Insurance Agency might stop the pension if it finds out?

A retiree has the right to engage in any permissible work they desire, based on the Almighty's saying: "It is He who made the earth subservient to you, so walk in its regions and eat from His provision, and to Him is the resurrection." However, it is not permissible for him to combine an early retirement pension with wages from another job if the retirement pension is a grant, because the concerned authority has prohibited this. But if the retirement pension is merely a deduction from the salary that was invested, then he has the right to combine the new work with the retirement pension, based on the hadith (definition): "Muslims are bound by their conditions."