1)
What is "Beli'al"?
1.
Radak: It is evil.
2.
Radak citing Midrash Shmuel 6:1: They Balu (faded away) Shem Shamayim from them. They said, there is no kingdom in Shamayim.
3.
Malbim: They cast off of themselves the Ol (yoke) of Shamayim. 1
1
Sifri (Re'eh 93:14): Beli'al (regarding Ir ha'Nidachas) is Bli Ol - they cast off Hashem's yoke.
2)
What is the meaning of "Lo Yad'u Es Hashem"?
1.
Refer to 2:12:1:2.
2.
Radak: They did not know Hashem's way. They did evil with their Kehunah, like the verse will say.
3.
Radak citing Targum Yonasan: They did not know to fear Hashem.
