Ibn Majah

Benefits and Issues:
The practice of the Rightly Guided Caliphs (khulafa’ rashidun) is Sunnah and can be presented as evidence.
The Prophet (sallallahu alayhi wa sallam) said:
“Adopt my Sunnah and the Sunnah of my Rightly Guided Caliphs.” (Jami‘ al-Tirmidhi, al-‘Ilm, Chapter: What has been reported regarding adherence to the Sunnah and avoiding innovation, Hadith: 2672)

Hadith Commentary: Benefits and Issues: "He did not vomit until he drank it":

Vomiting of wine cannot occur without drinking it. According to the preferred opinion of Imam Malik and Imam Ahmad, the testimony of vomiting wine establishes the act of drinking wine; therefore, the prescribed punishment (hadd) becomes obligatory upon him. However, according to Imam Abu Hanifah and Imam Shafi'i, the prescribed punishment does not become obligatory merely due to vomiting wine, because it is possible that he drank it under compulsion, in a state of necessity, or due to a misunderstanding. But according to Allamah Taqi, the position of the Malikis and Hanbalis is stronger, because it is supported by the verdicts of the Rightly Guided Caliphs, it is also supported by reason, and the current deteriorated circumstances also demand this. Therefore, Imam Nawawi has given preference to this view. (Takmila, vol. 2, p. 505)

"Let him bear the heat who has enjoyed the drink":

This is a proverb, the purpose of which is that whoever enjoys the benefit and profit of something, if there is any harm in it, he should also bear it himself. And the intent of Hasan radi Allahu anhu was that since Uthman radi Allahu anhu is enjoying the conveniences of the caliphate, then this difficult and severe task, which will create resentment and hatred in the hearts of the limited circle and his relatives, should also be carried out by him personally. However, Uthman radi Allahu anhu, out of respect and honor for Ali radi Allahu anhu, entrusted this responsibility to him.

In Sahih Bukhari, in the virtues of Uthman radi Allahu anhu, it is mentioned that Ali radi Allahu anhu had eighty lashes administered, and the reconciliation between the reports is as follows: as is found in some narrations, forty lashes were administered, but the whip had two ends. Therefore, whoever considered the number of lashes said forty, and whoever considered the two ends of the whip said eighty. In this way, it is as if striking forty double lashes was considered a preferred practice. Therefore, the meaning of "every Sunnah" can be that both eighty lashes and forty double lashes are Sunnah, and the suggestion to administer eighty lashes was itself given by Ali radi Allahu anhu. (Fath al-Bari, vol. 12, p. 85) as has been mentioned above.