Bukhari

Hadith Commentary:
It is well-known that Angel Jibril (alayhis salam) came to the Prophet (sallallahu alayhi wa sallam) in the form of Dihyah al-Kalbi (radi Allahu anhu).
Allah Ta'ala has granted the angels the ability to appear in whatever form they wish.
From this hadith, the truthfulness of the Messengerhood of the Prophet (sallallahu alayhi wa sallam) is established.

Hadith Commentary:
➊
Dihyah al-Kalbi (radi Allahu anhu) was a renowned Companion and was very handsome and dignified. When Jibril (alayhis salam) would come in human form, he would often take on the appearance of Dihyah al-Kalbi.
➋
In this hadith, there is mention of Jibril (alayhis salam), and he used to inform the Messenger of Allah (sallallahu alayhi wa sallam) of matters of the unseen. In this regard, this hadith is a proof of Prophethood. (Umdat al-Qari: 367/11)
➌
Abu Uthman narrated this hadith using an expression of uncertainty, but Imam Bukhari (rahimahullah) clarified at the end of the hadith that he had heard this narration from Usamah ibn Zayd (radi Allahu anhu), therefore there is no possibility of weakness or the like in it. And Allah knows best.

Hadith Commentary: Dihyah al-Kalbi was a handsome Companion. When Jibril (alayhis salam) would come to the Prophet (sallallahu alayhi wa sallam) in human form, he would appear in his likeness.

Hadith Commentary:
1.
Hazrat Dihyah Kalbi radi Allahu anhu was a very handsome Companion.
When Hazrat Jibril alayhis salam would come to the Messenger sallallahu alayhi wa sallam in the form of a man, he would appear in the likeness of Hazrat Dihyah Kalbi radi Allahu anhu.
It is narrated from Hazrat Aisha radi Allahu anha that she saw a mounted man who was engaged in conversation with the Messenger of Allah sallallahu alayhi wa sallam.
When the Messenger of Allah sallallahu alayhi wa sallam arrived, she asked:
"With whom were you conversing?" He replied:
"Whom do you think he resembled?" She said:
"Dihyah bin Khalifah Kalbi."
The Messenger of Allah sallallahu alayhi wa sallam said:
"That was Hazrat Jibril alayhis salam, and he was instructing me to go towards Banu Qurayzah."
2.
From these narrations, it is understood that the angel of revelation would appear to the Messenger sallallahu alayhi wa sallam in human form.
Imam Bukhari rahimahullah has described the manner in which the angel of revelation would come, that sometimes he would come in human form.
And Allah knows best.
(Fath al-Bari: 8/9)