What is the meaning of "Yode'a Hashem Derech Tzadikim"?
Rashi: He knows the way of Tzadikim, and it is in front of Him, to recognize it [and reward those who went in it], but the way of Resha'im is hateful in His eyes, and he passes it from in front of Him. This is why Resha'im will not stand on the day of judgment, to be written with Adas Tzadikim!
Radak: He recognizes [the way of Tzadikim] and supervises to benefit them. Similarly, "Mah Adam va'Teda'ehu" (144:3), "Asher Yeda'o Hashem" (Devarim 34:10), "Ki Yadati Es Mech'ovav" (Shemos 3:7), "Yadata Es Tzaras Nafshi" (below, 31:8), "Ani Yedaticha" (Hoshe'a 13:5). Similar to this is "v'Ein Li Makir" (below, 142:5), "Yehi Makirech Baruch" (Rus 2:9). Hashem gathers Nefashos of Tzadikim to Himself, and recognizes them to satiate them from His goodness, His knowledge and His supervision. This is the greatest good and reward - "v'Haysah Nefesh Adoni Tzerurah bi'Tzror ha'Chayim Es Hashem Elokecha" (Shmuel I, 25:29)!
Malbim: This Yedi'ah is the one who receives intellect clinging to the one who gives intellect, like it says "Ki Yadativ Lema'an Asher Yetzaveh Es Banav v'Es Beiso Acharav" (Bereishis 18:19). I.e. he clings to knowing Me. This is only for eternal matters that do not change. Tzadikim go on the path that ascends to Beis Kel, to love Hashem and cling to Him. It is not separated from knowing him, and is eternal, like Him. Therefore they remain forever.
What will happen to Resha'im?
Radak: Their Nefashos will perish - "v'Es Nefesh Oyvecha Yekal'enah b'Soch Kaf ha'Kela" (Shmuel I, 25:29).
Rikanti (Shemos 33:19): 'Has no share in the world to come 1 ' means that he does not have his own dwelling and storehouse there, but he stands where many stand. Alei Shor 2, p.303 - Rosh Hashanah 17a says that Gehinom will finish, but the [greatest] sinners of Yisrael will not finish. The Vilna Gaon said that nine parts of the Nefesh can be cut off from the world to come, but the 10th cannot be cut off. R. Meir Eliyahu Shlita, based on Kabalah - one who died amidst Kares will never come to the higher Gan Eden, only to the lower Gan Eden.
Malbim: Their oath is to the depths of the pit, to matters that wear out and are lost. They are not tied to knowing Hashem. Therefore it is lost in the end, as if it was not.
Sanhedrin 90a lists seven who have no share. Those who expound hints [in verses] say that even they (the six Jews among them) come to the world to come (ibid., 104b). R. Moshe Shapiro Ztz"l, based on Rama mi'Pi'ano - surely the Halachah follows them. The Neshamah of a Jew is taken from Kisei ha'Kavod. Surely it is eternal! Margoliyos ha'Yam (104b, 18) - there is no argument. All Jews come to the world to come, but not all receive a share above what they merited.
