What is the ruling on the wage received by an applicant from another employee for performing the work assigned to the original employee, given that the applicant is aware that the company is unaware of this agreement?

It appears that an employee's work outside of their official working hours makes them a common employee, not a private one. A common employee is permitted to hire someone else to perform the required work without the employer's knowledge, unless it was stipulated that they must perform the work themselves, or if the nature of the work varies depending on the person.

Dr. Abdullah Al-Ammar mentioned the conditions for the permissibility of "subcontracting" (leasing out a lease) if the employee is a common one: 1. That the employer does not stipulate that the employee must perform the work themselves. 2. That the work is not such that its quality varies depending on the person (e.g., calligraphy). 3. That the first employee is not a private employee. 4. That the first contract has not expired.