Is moonlighting an offense against Ten Commandments?

Government employees of many countries are prohibited by the respective conduct rules, from taking up any employment of monetary gain, on the assumption that they are 24x7 for the Government. From the employees' perspective, many find it difficult to save enough after paying the taxes and hence resort to working outside official duty time and on holidays. Such an activity is called 'moonlighting'. If caught, the employee is liable for action under the service rules. But, one doubts if moonlighting by a Christian employee goes against any of the Ten Commandments. If it does, which is the Commandment attracted? Inputs from scholars of any denomination are welcome.