Why did he curse the one who informed his father of his birth? If he is alive, the curse can harm him!
Radak: Yirmeyah found out that Pashchor was the informer. (He deserved severe punishment, like it says at the beginning of this Perek. - PF)
Malbim: Yirmeyah teaches that the man already was cursed. Menasheh killed him, for he made my father rejoice.
Why did he say "Some'ach Simchaso"?
Radak: He made my father happy. People are happy with the birth of a son, and worry about birth of a female. Had my father known that my end will be suffering and grief (verse 18), he would not have rejoiced over me.
Why is there a Dagesh in the Mem in "Some'ach"?
Rashi: It means to make others happy; he made my father happy.
