Why does it say "Ish Echad"?
Bamidbar Rabah 10:5: Echad always means Gadol, i.e. the greatest of his generation. 1
Malbim (Shmuel 1:1:1): He was special, to father Shimshon. Perhaps he holds that Bamidbar Rabah can agree that he was an ignoramus. (PF)
Why does it say "Mishpachas ha'Dani"?
Radak: Mishpachas is like Shevet, as in "Mishpachas Yehudah" (Yehoshua 7:17). The Yud at the end of ha'Dani is Leyaches (to attribute to it), like "Shevet ha'Menashi" (Devarim 29:7).
Why does it say both "Akarah" and "Lo Yaladah"?
Radak: The latter adds explanation, like "Sarai Akarah Ein Lah Valad" (Bereishis 11:30).
Toras Moshe (Haftoras Nasa): A man can divorce (without paying a Kesuvah) a woman who vows, for children die due to the sin of Nedarim. The angel told her that she will never have children if not for this vow 1 , so Mano'ach cannot object.
Alshich, Malbim: There can be a woman who gave birth, and later became sterile. Also, there can be a woman who did not give birth for another reason, but she is not sterile. 2
