What do we learn from "Pri Tzadik Etz Chayim"?
Refer to 11:30:2:2.
Rashi: The reward for Peros of deeds of Tzadikim, it is a tree that lives forever.
R. Yonah: "Pri Tzadik" are his sons. They are Etz Chayim, for he rebukes them in their youth, and is wise to chastise them and raise them for life - "Chanoch l'Na'ar Al Pi Darko Gam Ki Yazkin Lo Yasur Mimenu" (22:6).
Malbim: A Tzadik uses the laws of Chachmah to do Tzedek in deed. He is compared to a tree that bears fruits; he and his friends eat the fruits, i.e. their deeds that result from natures of their Nefashos. Eating such Peros is like eating from Etz ha'Chayim - it causes the Nefesh to live forever, i.e. one who learns from his deeds and does like him.
What is the significance of "v'Loke'ach Nefashos Chacham"?
Bava Basra 11a: This applies to King Munvaz. He opened his ancestors' storehouses in famine years to feed the poor. His family protested 'you are squandering what your fathers saved! He answered, they stored in a place where others might take it, and in a way that does not increase. I stored [above], in a place where no one can take it, and in a way that increases - "Fri Ma'aleleihem Yochelu." They stored money, for others, for this world. I stored souls, for myself, for the world to come.
Bava Metzi'a 85a: R. Elazar b'Rebbi Shimon died and left an evil son. Rebbi gave him the title of 'Rebbi', and asked R. Shimon ben Isi teach him. He became a Chacham. "Pri Tzadik Etz Chayim" refers to R. Yosi b'Rebbi Elazar b'Rebbi Shimon. "V'Loke'ach Nefashos Chacham" refers to R. Shimon ben Isi.
Rashi: A Chacham acquires Nefashos - he teaches to them the good path, and it is as if he acquired them - "v'Es ha'Nefesh Asher Asu v'Charan" (Bereishis 12:5).
R. Yonah: It is possible that a Tzadik did not engage in learning Chachmah, only in proper deeds. He cannot draw people's hearts to accept his rebuke. However, his sons are under his hand, and they heed him. He guides them in the way of Chachmah from their youth. However, all heed a Chacham's words. He draws the hearts of people (not only his sons) to the way of life, and brings the matters to their hearts via his Chachmah.
Malbim: A Chacham gathered the laws of Chachmah via learning from his Rebbeyim. He draws Nefashos via teaching to them the laws of Chachmah.