Our Gemara on this daf discusses the halakhic concept of הנדר שהותר מקצתו. הותר כולו if a portion of a vow is deemed null, then the entire vow may be rendered invalid.

As we discussed in Psychology of the Daf Nedarim 22, there are two legal mechanisms to annul a vow.  Beis Din must either come up with a reason that you “regretted” having made it, known as “charata”, or that there was a certain circumstance that you were unaware of which, had you known, you would not have vowed, known as “pesach”.  

“Pesach” is deeper because it creates a legalism which is used to induce a legitimate clause of an unforeseen reality that he was unaware of. This makes the oath, technically, under false pretenses, so the Beis Din can annul it. While “charata” is simply delving into the psyche of the person who has come to a point where he regrets and truly would not have made the vow.

Shulkhan Arukh YD 228 discusses an opinion that though we say if a portion of a vow is deemed null, then the entire vow may be rendered invalid, that only applies to “pesach”, but not “charata”.  We can understand the logic, as “pesach” legally makes the vow like an erroneous action under false pretenses, while “charata:, though similar, is weaker. Yes, technically the person now regrets and never would have made it, but there was no unknown external circumstance. 

The Chida (Rosh Dovid VaEschanan, 58) cleverly reads this into Moshe’s argument that he should be allowed to enter the Land of Israel.  He claims, since God allowed him to conquer Sichon and Og which is an annexation of Israel, obviously God partially annulled His vow. Thus partial annulment leads to full invalidation of the oath.  However, God argues back that this is only true by “Pesach”, but not with “Charata”.  Since God can never utilize the legalism of “Pesach”, since He can never have been unaware of something, he must use “charata”.  God paskened, so to speak, that charata does not activate the principle of הנדר שהותר מקצתו הותר כולו if a portion of a vow is deemed null, then the entire vow may be rendered invalid.

You might ask on the Chida, true God cannot be said to be unaware of something, but how can you say God regrets either?

In fact, we see in the commentary and Midrash Bereishis (6:6) that God cannot regret, as this is an imperfection of mortals:

וַיִּנָּ֣חֶם ה כִּֽי־עָשָׂ֥ה אֶת־הָֽאָדָ֖ם בָּאָ֑רֶץ וַיִּתְעַצֵּ֖ב אֶל־לִבּֽוֹ

And Hashem regretted having made humankind on earth and was sorrowful in His heart.

Rashi, quoting Bereishis Rabbah 27:4, reframes the word “Yiynachem” “Regret”, as “comfort”, such as in the phrase, Nichum Aveilim, comforting the mourners:

“It was a consolation to Him that He had created man on earth, for had he been one of the heavenly beings he would have incited them also to rebel against God.”

Ibn Ezra is more direct, and states:

The Torah spoke in the language of men, In other words, And it repented is an anthropomorphism. for we know that God is not a man that he should repent. This term is used because if a human being acted in the way God did, destroying his creation, it would be said of him that he repented.

However, we might be able to understand the Chida if we study the Bartenura’s explanation of this verse, where he uses the Latin term, “Supra Pensari” which literally translates as a “High Judgment”.  The gist of the Bartenura is that God does not regret or change His mind, but the circumstances changed sufficiently to activate a different interactional outcome with God’s will.  (See Psychology of the Daf, Nedarim 8 for more about this idea.)

Even so, how do we explain the Chida?  I believe that since, even anthropomorphically, we use the term of regret in regard to God, Ein Bo Ela Chiddusho, we cannot derive anything in addition to the unusual idea. (That is when encountering a novel legal principle, one cannot derive anything further since it is without precedent, for example see Sanhedrin 27a). 

Thus, we can only activate the principle of “Charata” in regard to God’s vows, and not “Pesach”.  This is true legally if only to show deference and respect to God, let alone if somehow it had greater metaphysical implications.