Rabbi Eliezer says we can make an opening [through which a person can escape from his rash vow] for the sake of his father and mother’s dignity [had he thought of them, he wouldn’t have taken the oath]. But the Sages forbid this. Rabbi Zadok says if you are giving him an opening for the sake of his father and mother, then give him the opening for the glory of God! If so, there would be no oaths left! But the Sages agree with Rabi Eliezer if the oath was a matter between him and his parents [i.e., he promised not to accept any gifts from them] then we can make him an opening for his father and mother’s dignity.
This Mishnah is hard to understand, unless you know about oaths. The Sages realized that oaths were binding on people and that there was flimsy basis for releasing people from vows. They created such an “opening” for release by arguing that “had he known” or “had he remembered” or “had he realized,” the man would never have taken the oath. Rabbi Zadok extends Rabbi Eliezer’s reasoning to the point of absurdity. The Rabbis kept the category of oaths intact, but continued to look for ways to release people from rash vows.