What is "Nachalas Hashem"?
Radak: It is the best thing that Hashem can give to a person in this world.
Who gets "Nachalas Hashem"?
Rashi: That man (Hashem's dear one). Radak - David said so about himself; Shlomo is a great inheritance for me!
Who are the "Banim"?
Rashi: They are the Talmidim that he established; they are like sons to him.
What is "Sachar Pri ha'Baten"?
Nidah 71a: If a man delays Hazra'ah while on his wife's stomach, in order that she will be Mazri'ah first, Hashem rewards him with fruit of the stomach (sons).
Rashi: It is reward of fruits of Torah in the heart - "Ki Na'im Ki Sihmerem b'Vitnecha" (Mishlei 22:18).
Radak: The matter is repeated in different words. The reward that Hashem gives to man in this world for his good deeds is children.
Malbim: He already said that man's efforts do not help to carry out a project, guard acquisitions or bring food. Now he says that also to beget children and raise them is a gift from Hashem. For Avodah and Pe'ulah, one is paid per hours. For love and closeness, they give an inheritance that stands forever. So, for merit and Mitzvos, one's wage is children - his wife will not be barren. If one is closer to Hashem and good in front of Him, he gets an enduring inheritance - children who will establish his inheritance for generations.
