Bismillahi Rahmani Rahim
Sisters, I have a degree in Journalism, and consider myself well-versed when it comes to words, however, the difference between these two words was never taught to me in any of the Colleges nor the University I attended. So, I decided to look them up myself.
What I found out is that who and whom are both pronouns, however WHO is used when referring to the SUBJECT of a question and WHOM is used when referring to the OBJECT of a sentence/question.
For example, I could ask, “Who ate the last piece of Bean Pie?”
“Who” is the subject because it is referring to the person who ate the last piece of Bean Pie. The subject of a sentence is the person doing the action.
On the other hand, if I ask, “To Whom did you serve the last piece of Bean Pie?”
“Whom” is the object of the sentence because it is referring to the person to whom the action was directed.
Here is another example.
“Whom are you courting, Brother?”
The Sister who is being courted is the OBJECT of the courtship as well as the question, so it would be grammatically correct to use the pronoun WHOM.
Conversely, if you were to ask the Sister the same question, you would ask, “Who is courting you, Sister?”
The Brother who is doing the courting is the SUBJECT of the courtship as well as the question, so it would be grammatically correct to use the pronoun WHO.