Bukhari

Hadith Commentary:
➊
The intention of Imam Bukhari rahimahullah is that the validity of prayer does not depend on the number of garments, but rather on the covering of the private parts (satr al-awrah), regardless of how that is achieved.
In the presented narration, Jabir radi Allahu anhu prayed in a single sheet and, to cover his private parts, he tied both ends of the sheet around his neck.
It is also understood from this that if someone has more than one garment but still prays in only one, it is permissible to do so, although it is better to pray in a complete dress. Thus, in the first narration, the action of Jabir radi Allahu anhu is described.
From the second narration, it is learned that Jabir radi Allahu anhu prayed in a single garment because he had seen the Messenger of Allah sallallahu alayhi wa sallam pray in a single garment. However, a contrary narration is transmitted from Abdullah ibn Mas'ud radi Allahu anhu, as he said:
No man should pray in a single garment, even if it is as vast as the earth and sky.
The hadith scholar Ibn Battal rahimahullah has attributed a similar prohibitive ruling to Ibn Umar radi Allahu anhu.
In the end, there was consensus that prayer can be performed in a single garment, provided it covers (the awrah), even if other garments are available.
(Fath al-Bari: 1/607)

➋
In Sahih Muslim, it is narrated that the one who reported from Jabir radi Allahu anhu about praying in a single garment was Ubadah ibn Walid.
From a narration in Sahih Bukhari (360),
it is known that Sa'id ibn Harith asked about this matter, while in another narration in Sahih Bukhari (370),
Ibn al-Munkadir says:
We said:
O Abu Abdullah!—meaning, we asked about this matter.
It is possible that on multiple occasions, different people asked about this issue.
In response to Ibn al-Munkadir, Jabir radi Allahu anhu said:
I wanted ignorant people like you to see me praying in this manner.
From Jabir radi Allahu anhu's answer, it is understood that one should not object to the actions of the senior scholars without proper investigation; rather, in the view of the noble Companions radi Allahu anhum ajma'in, doing so is foolishness and ignorance.
What Jabir radi Allahu anhu meant was that I did this intentionally, and there is absolutely no room for your objection in this matter.
You should have considered that a Companion knowledgeable of the Shari'ah is performing this action, and in this action, neither intellect nor analogy has any place; therefore, this action itself is proof of its permissibility. But instead of deriving a ruling from this action, you began to object, which is a sign of foolishness and ignorance.
(Fath al-Bari: 1/606)

➌
(Mushkhab)
does not mean the common stool (table) found among us, but rather it refers to three sticks being stood upright, their upper ends joined together and their lower ends spread apart, just as soldiers in a parade ground stand three rifles together. At that time, people would place their clothes on this wooden stand during ritual bath (ghusl) and other times, and they would also hang water skins on it to cool the water. Shepherds would also use it, meaning they would hang their bucket and water skin on it.
(Fath al-Bari: 1/606)