2,724. Starting Hilchos Nedarim

Hilchos Shevuos 12:12

It is permitted to ask a Torah scholar to absolve an oath as has already been discussed, and there’s nothing wrong with doing so. In fact, one who has his doubts about the practice is having heretical thoughts. Still, it would be appropriate to tread carefully in this matter. One shouldn’t absolve an oath except for purposes of a mitzvah or if there’s some pressing need. It’s a great benefit never to make an oath at all; if one violated and did so, it would be better for him to endure the difficulty involved in keeping his oath as per Psalms 15:4-5, “One who swears to his own detriment and doesn’t retract... he who does these things will never falter.”

Hilchos Nedarim 1:1

There are two types of vows. The first prohibits oneself from things that would otherwise be permitted to him, such as if he said, “Produce from country X is prohibited to me for 30 days” or “...forever,” or if he said, “Produce Y is prohibited to me” or “This produce is prohibited.” Such things become prohibited to him regardless of the language in which he spoke the prohibition, even though he didn’t make an oath, and even though he didn’t use God's name or a term we use to describe Him. Regarding this, Numbers 30:3 says, “To prohibit a prohibition upon himself,” i.e., to render permitted things prohibited to him. Similarly, a vow of this type will take effect if one says: “They are prohibited to me.” The Rambam calls vows of this type “vows of prohibitions.”