What is the meaning of "Mokesh Adam Yala Kodesh"?
Sanhedrin 58b: If one slaps a Yisrael's face, this is like slapping the Shechinah's face.
Rashi: When a man stumbles in sins, he ruins his Kedushah. This is like "v'Shasu v'La'u" (Ovadyah 1:16).
R. Yonah: This is next to "v'Adam Mah Yavin Darko", for one cannot guard from traps and stumbling blocks. Rather, he hands over his Nefesh to Hashem. However, the traps that he can beware of them, they are traps of sin. One should investigate his ways; if there is sin, distance it! If one remembers that he benefited from Hekdesh, he should repent. He pays his benefit and an added Chomesh, and offers a Korban Asham.
Malbim: One of the traps in which man is caught is sins of his lips. One must guard them lest they set a trap for him. One trap is "Yala Kodesh", if he is quick to make Hekdesh without contemplating well
Why does it say "v'Achar Nedarim Levaker"?
Nedarim 22a: A vow causes one's deeds to be scrutinized.
Rashi: One must pursue Korbanos to vow, bring and request [pardon] for his Nefesh.
R. Yonah: One must investigate whether he vowed to Hashem, and [if so] "Motza Sefasecha Tishmor v'Asisa" (Devarim 23:24), and not delay to fulfill. Also Nedarim are a trap for a person, if he vows and does not fulfill. Man can avoid this trap! He should fear for his Nefesh lest he stumble in this and be punished Midah k'Neged Midah. If he profaned his vow, or benefited from his Kodesh due to lust for money, he will lose his money in an evil way. One must check his ways for matters to fix, e.g. if he is holding stolen money, he must return it. Perhaps he vowed and does not remember it; therefore, he must check his vows 1 .
Malbim: Another sin of the lips in which man is caught is if he makes many vows. He can stumble easily in this via benefit from Hekdesh or delaying fulfilling them.
I.e. Stam he does not remember, but if he puts to his heart to investigate, perhaps he will remember. (PF)