Shalom Shmuel,

Thank you for your thoughtful question! I understand that you want to know why the Mishnah teaches two cases of sending a second Shali'ach.

By the way, I don't think we see the Gemara teaching us that the husband would be Matri'ach a Shali'ach to bother his wife. Also, I don't think we are looking at an instance of an ex-wife per se, because we are discussing cases in which the divorce does not carry through.

To me, it would make sense for us to review together both the cases in the Mishnah and also the Chidush which the Gemara says each case is teaching us.

Case #1. The husband himself meets up with and cancels the Shali'ach before that Shali'ach reaches the wife. The Chidush is that we assume the husband genuinely intends to cancel the divorce even if he met the Shali'ach incidentally, without actively pursuing him.

Case #2. The husband sends a second Shali'ach to meet up with and cancel the first Shali'ach before that first Shali'ach reaches the wife. The Chidush is that a second Shali'ach has the power to cancel the first Shali'ach.

Case #3. The husband meets the wife herself to cancel the divorce before the Shali'ach arrives to her. The Chidush is that we don't assume the husband is merely trying to vex his wife. Rather, we assume he sincerely intends to cancel the divorce.

Case #4. The husband sends a second Shali'ach to meet the wife and cancel the divorce before the first Shali'ach arrives to her. The Chidush is that even in this case, where the husband didn't make the effort to visit the wife himself, we still don't assume he sent the second Shali'ach merely to vex his wife. Rather, we assume that he sincerely wants the second Shali'ach to cancel the divorce.

So, to my mind, the response to your question ("Why does the Mishnah say both times 'or through a Shali'ach?'") that makes the most sense would be: In case #2 we learn only that one Shali'ach can override a previous one, but not that it's wrong to assume sending a Shali'ach to the wife is intended merely to vex her. And in Case #4 we learn only that it's wrong to assume that sending a Shali'ach to the wife is intended merely to vex her, but not that one Shali'ach can override a previous one.

Bi'Vrachah,

Yishai Rasowsky