Is it permissible to choose the punishment of an employee's termination from work as a response to his misconduct?

It is permissible for the wronged to seek redress for themselves to the extent of the injustice done to them. However, it is better for them to be patient and to forgive, as Allah Almighty says: "and those who restrain anger and pardon people." It is not permissible to transgress against the oppressor beyond the extent of their injustice, for "The recompense of an evil deed is an evil deed like it." As for dismissing an employee due to their insults, this is not considered a Sharia-prescribed punishment; rather, the employer assesses this if their continued presence would cause harm. We encourage the questioner to forgive; otherwise, they may seek retribution without transgression, acting upon the words of Allah Almighty: "So whoever has assaulted you, then assault him in the same way that he assaulted you."