What matters should one grasp?
Rashi: Tzedek and Resha. If a Navi tells you something that appears to be evil, like Shmuel told Sha'ul [to kill all people and animals of Amalek], do not have reservations about it.
Ibn Ezra: I explained above the parts of the Nefesh (refer to 7:3:3:2). A wise man gives to each Nefesh what is proper in its time. He need not search what to do; he follows the Torah, and does not veer from it right or left. He guards the Mitzvos "Asher Ya'aseh Osam ha'Adam va'Chai Bahem" (Vayikra 18:5) in both worlds. And so he concluded the Sefer ("Sof Davar ha'Kol Nishma Es ha'Elokim Yera v'Es Mitzvosav Shemor Ki Zeh Kol ha'Adam" - 12:13).
Rashbam (here and 16): Be a Tzadik, and do Resha (transgress a light Mitzvah) when needed [for Piku'ach Nefesh].
Ri Kara: Tzedek and Chachmah. Do not say, since excess Tzedek and Chachmah are Meshomem, I will slacken from them.
Rid #1: Tzedek and Resha. Be intermediate. Marry a woman, eat meat, and be careful of the Isurim of Nidah and blood as much as you can. If you stumble b'Shogeg, this is not considered Avon 1 (intentional sin).
Rid #2: Chachmah and Sichlus. Be intermediate. Eat, drink and wear nice clothing.
R. Avigdor: Mikra and Mishnah.
Seforno: Your primary efforts should be to acquire eternal perfection. Do not totally neglect efforts for temporary life. Orchos Tzadikim (Sha'ar ha'Simchah DH Ach Atah) - one must designate time for Avodas ha'Torah and Avodas Olam ha'Zeh. One may not cause a loss to the other.
Metzudas David: He should fear a terrifying matter. However, the heart should not be too distracted.
Sometimes Chet is considered like Avon, if he should not have entered the situation, e.g. he swore without need. (PF)
What is "Tanach"?
Metzudas Tziyon: It is an expression of abandoning.
Who is "Yere Elokim"?
R. Avigdor citing Koheles Rabah: It is someone like R. Avahu. Maharzu (on the Midrash) - he enacted to hear Teki'os on Rosh Hashanah in a way that fulfills all opinions.
Seforno: He guards His intent.
Metzudas David: It is one who fears a terrifying matter, but not too much. One who fears too much, it is as if he removes his trust from Hashem. One who does not fear at all is not concerned for Hashem's decree - He sent this to scare people!
What is the meaning of "Yetzei Es Kulam"?
Rashi: He fulfills both Tzedek and Resha like their laws.
Rashbam: He guards himself - he is not too virtuous, nor too evil. All his deeds are l'Shem Shamayim.
Rid: He fulfills both of these Midos.
R. Avigdor: He has Mikra and Mishnah.
Seforno: He enters in Shalom and leaves in Shalom. Via the two kinds of efforts, he attains the intended purpose.
