What are the implications of "Lefalei Neder O Nedavah"?
Rashi (in Sotah, 15a): It implies that only a Korban Nedavah 1 requires a Minchas Nesachim, but not a Chatas or an Asham.
A Shelamim, a Todah and an Olas Nedavah.
Why does the Torah require that one brings an Olah or a Shelamim upon entering Eretz Yisrael?
Rashi: What the Torah means is that, upon entering Eretz Yisrael, if one fancies 1 bringing a Korban Neder or Nedavah, then it must be accompanied by a Minchas Nesachim.
Why does the Torah see fit to mention "be'Mo'adeichem" separately?
Rashi: Because the Korbanos of Yom-Tov are not voluntary but obligatory. 1
What happened o the Minchas Nesachim?
Rashi (citing Succah, 48b): The Minchah, including the oil that was mixed together with it, was burned, and the wine poured into the bowls on the roof of the Mizbe'ach.