What is the ruling on repeatedly saying "May Allah fight you" in different situations?

It is not permissible to supplicate with "May Allah fight him" because its meaning is that He kills you, curses you, or treats you as an enemy. Supplicating against a Muslim with a curse is not permissible, for cursing a believer is like killing him, and a believer is not a frequent curser. Those who frequently curse will not be witnesses or intercessors on the Day of Resurrection. What has been reported from the Companions, their saying "May Allah fight Samura," is interpreted as intending severity and admonition, not a curse.