Yitzchak Avinu telling Esav what happened

Question

My son-in-law asked me an interesting question: Yaakov left with the blessings, and Esav came in. Yitzchak tells his son that he can't bless him because (https://www.sefaria.org/Genesis.27.35?lang=bi&with=all&lang2=en)

וַיֶּחֱרַ֨ד יִצְחָ֣ק חֲרָדָה֮ גְּדֹלָ֣ה עַד־מְאֹד֒ וַיֹּ֡אמֶר מִֽי־אֵפ֡וֹא ה֣וּא הַצָּֽד־צַ֩יִד֩ וַיָּ֨בֵא לִ֜י וָאֹכַ֥ל מִכֹּ֛ל :בְּטֶ֥רֶם תָּב֖וֹא וָאֲבָרְכֵ֑הוּ גַּם־בָּר֖וּךְ יִהְיֶֽה ׃וַיֹּ֕אמֶר בָּ֥א אָחִ֖יךָ בְּמִרְמָ֑ה וַיִּקַּ֖ח בִּרְכָתֶֽךָ׃
Isaac was seized with very violent trembling. “Who was it then,” he demanded, “that hunted game and brought it to me? Moreover, I ate of it before you came, and I blessed him; now he must remain blessed!... Your brother came with guile and took away your blessing.”

Why was Yitzchak allowed to say this to Esav? Isn't it lashon hara, and rechilus? Lashon hara because he is saying something negative about Yaakov, and rechilus because as a result Esav hated his brother and wanted to kill him!
It's clear from the verse that Yitzchak was extremely shocked, but still, we would not have expected one of the Avos Hakedoshim to do something terribly wrong even when caught by surprise. And, I don't know of a source saying that he did this wrong - maybe others could correct that.

Answer 1

I once was eating by someones house and he asked the above mentioned question. He answered that it was for toeles, by stirring Esav to hate Yakov that would keep clal Yisrael on track to do ratzon hashem. I think this is good according to the Arizal that Yischak knew Esav was a rasha and wanted to give him the blessings for this very reason, so that clal yisrael won't deviate from the ratzon hashem.

Answer 2

I want to post what my own family discussed when the question came up, as some of the suggestions may be helpful.

1. My son-in-law asked his Rav, who said that it technically is not going to be lashon hara, because there was no way that Esav was not going to find out.
   That does help in the rules of lashon hara, but of course there are more conditions.
2. My wife didn't buy that, I think. Why couldn't Yitzchak make some excuse why he wouldn't give a blessing? "Come to think of it, I'm just not hungry - can't eat another bite!" probably wouldn't cut it :), but why couldn't Yitzchak just truthfully have quoted Rashi: "He felt gehinnom come in with Esav".
3. My other son-in-law suggested (like Schmerel's answer above) that Esav needed to hear what Yitzchak said, גם ברוך יהיה. When he eventually found out that Yaakov was blessed, he needed to know that his father agreed. As Rashi says in his name, "Don't think that if he hadn't fooled me, he wouldn't have gotten the blessings." Esav needed to know that cheated or not, the result was the right result and he must learn to live with it.
4. I suggested the flip side of that: Esav needed to hear that his father knew that he had been fooled. If you know you've been wronged, it's very painful if no one is willing to acknowledge it and pretends nothing happened. "Ah - just get over it! Are we still talking about this?"
   In the long term, Esav is going to need to be able to (partially) reconcile with his brother. That could only happen if he understood what had happened and knew that his father understood.

Answer 3

Two ways to answer it from different angles.

Many Rishonim and Onkeles explain בְּמִרְמָ֑ה to mean wisdom. IOW he aced you out I now agree to having given him the brochas. Yitzchok said גַּם־בָּר֖וּךְ יִהְיֶֽה which indicates an apparent agreement towards giving Yaakov (whoever came first) the Brochas. Therefore he was in essence saying "take this up with ME not Yaakov" and was doing the opposite of speaking Loshon and Rechilus. He was taking blame away from Yaakov and putting it on himself.

Or you can say that Yitzchok was not agreeing to what Yaakov did and therefore felt there was a toelis (benefit) in telling Esav, that Yaakov received the Brochas. His further efforts to receive them is going to depend on Esav wresting them away from Yaakov. It would be similar to telling someone who robbed his store the night before

(note: there are many conditions of when Loshon hora and Rechilus may be spoken for toelis)

Answer 4

Although Yitschaq would assume Yaaqov deceived him, [Bereshit 27:12-13] established Yaaqov as innocent & Rivqah as the deceiver.

Yitschaq was innocently unaware of Rivqah's plan, when witnessing against Yaaqov in [Bereshit 27:35]. - The result of Yitschaq's testimony to Esav could potentially represent 'lashon hara' as described in [Shemot 23:7]. - Yitschaq's testimony caused Esav in [Bereshit 27:41] to vow harm upon Yaaqov (whose innocence was unknowingly declared by Rivqah).

What Halakhic consequences apply to Yitschaq if found guilty of Lashon Hara?

Chofetz Chaim - [ The Prohibition Against Lashon Hara , Principle 4 : 12 ]

And if he transgressed and spoke lashon hara about his friend and came to repent, it [his repentance] depends upon this: If his friends rejected his words and his friend was in no way demeaned by this [lashon hara] in their eyes, if so, there adheres to him only the sin of "between man and his Maker" (and not that of between "man and his neighbor"), his having transgressed the will of the L–rd, who commanded this [that lashon hara must not be spoken], as we wrote above in the introduction. His correction is to regret what has passed, confess [his sin] and take it upon himself with a full heart not to repeat this [sin] in the future, as with all sins between man and his Maker.

But if his friend were demeaned by this in the eyes of the hearers and through this suffered physical or financial harm, or if he were caused [emotional] pain by this, this is in the category of all the sins between man and his neighbor, which even Yom Kippur and the day of death do not atone for until he conciliates his neighbor. He must, therefore, ask pardon of his friend for this, and when he is conciliated and forgives him, there remains with him only the sin of between man and his Maker, and he must do as mentioned above.

And even if his friend does not yet know anything about it, he must reveal what he did to him which was not in accordance with the din, and ask forgiveness of him for this, since he knows that through him this harm was done him. From this we can understand how much one must take care to guard himself from this pernicious trait [of lashon hara], for if one is steeped in this, G–d forbid, teshuvah [repentance] is almost impossible for him. For he certainly will not remember all of the souls whom he grieved by this lashon hara. And even those people whom he remembers as having stirred up evil against will not know of it, wherefore he will be ashamed to reveal it to them. And sometimes 54 he will speak of a family taint and thereby harm all the future generations, so that he can never be pardoned for this.

As Chazal have said (Yerushalmi Bava Kamma 8:7): "One who speaks of a family taint never has atonement [for this]." Therefore, one must distance himself from this extremely pernicious trait, so that he not thereafter be, G–d forbid, [in the category of] "the crooked cannot be straightened" (Koheleth 1:15).

https://www.sefaria.org/Chofetz_Chaim%2C_Part_One%2C_The_Prohibition_Against_Lashon_Hara%2C_Principle_4.12.1?with=all&lang=bi