If it is asked: The hadith is worded in the masculine; so how can we use a feminine pronoun when the deceased is a woman?

The answer is that this hadith concerns a supplication for a male deceased person. Had the Messenger of Allah ﷺ said, “When you perform the funeral prayer over the deceased, say: O Allah, forgive him …,” then there would have been grounds for not using the feminine. Rather, we follow the wording of the text and interpret it in the manner appropriate to the case at hand.

If the deceased are two, you say: “O Allah, forgive them both …”

If they are a group, you say: “O Allah, forgive them.”

If they are a group of women, you say: “O Allah, forgive them.”

If they include both men and women, the masculine takes precedence, so you say: “O Allah, forgive them.” Thus, the pronoun is determined by those for whom the supplication is being made.

Similar to this in some respects is the hadith of Ibn Mas‘ud, may Allah be pleased with him, concerning the supplication for distress: “O Allah, I am Your servant, the son of Your servant, the son of Your bondwoman …” (1).

A woman says: “O Allah, I am Your bondwoman, the daughter of Your servant, the daughter of Your bondwoman …”

If a person does not know whether the deceased is male or female, should he use a feminine pronoun or a masculine one?

The answer is that either is permissible, depending on what is intended. If you say, “O Allah, forgive him,” meaning: this person, or the deceased; and if you say, “O Allah, forgive her,” meaning: this funeral bier.