Will a Muslim be rewarded for his work at the Commission for the Promotion of Virtue and the Prevention of Vice? Is it a noble deed, or is it better to continue with his current job?

Working in an environment where righteous people are abundant is better than working in an environment where righteous people are few. The General Presidency for the Promotion of Virtue and the Prevention of Vice performs a great work in preserving religion and spreading good. It is a safety valve for society from destruction, and working with them falls under the category of cooperating in righteousness and piety. Therefore, do not hesitate to work with them if you get the chance.