The ruling on invoking evil upon others in their absence or presence

Question:
Q: Is it permissible to invoke good or evil upon someone in their absence?

Answer:
If he invokes evil upon his brother: is he invoking for his brother or invoking against his brother? If he invokes against him, he is not invoking for him, he is invoking against him. It is not appropriate, it is not permissible, it is not permissible to invoke against his brother...
If it is retaliation, there is no harm. If his brother said to him, "May Allah kill you," and he said, "May Allah kill you," this is retaliation and there is no harm, he does not exceed it. The Prophet (peace and blessings be upon him) said: If he said, "May Allah kill you," and he said, "May Allah kill you and may Allah curse you," he has exceeded him in the second instance; the first is retaliation, and the second is injustice. Or if he said, "May Allah kill you," and he repeated it, repetition is a mistake. But if he said only what was said to him, for example, if he said, "May Allah disgrace you," and he said, "No, you, may Allah disgrace you," or: "May Allah kill you," and he said, "No, you, may Allah kill you," this is retaliation. And if he adds to it, he becomes an oppressor...
Invoking against someone, whether in his absence or in his presence, is all reprehensible and not permissible, except in the case of retaliation.