Bukhari

Hadith Commentary:
The esteemed Imam (rahimahullah) has narrated this hadith in several places for different purposes.
Here, his objective is to establish the permissibility of performing the Duha prayer (Salat al-Duha) in a state of residence (i.e., not traveling), and, on certain occasions, also to prove the permissibility of performing it in congregation.
Even if, according to the statement of Anas (radi Allahu anhu), the Prophet (sallallahu alayhi wa sallam) performed this prayer only on this occasion, then for the purpose of establishing the ruling, the Prophet’s (sallallahu alayhi wa sallam) performing an action even once is sufficient and conclusive.
In fact, there is evidence from several occasions that the Prophet (sallallahu alayhi wa sallam) performed this prayer.
It is possible that Anas (radi Allahu anhu) did not have the opportunity to be with the Prophet (sallallahu alayhi wa sallam) on those occasions.

Hadith Commentary:
(1)
From this hadith, it is understood that the Duha prayer (Salat al-Duha, also known as the forenoon or mid-morning prayer) was well-known during the era of the noble Companions (radi Allahu anhum), because the Messenger of Allah (sallallahu alayhi wa sallam) made a point to perform prayer at the house of an Ansari at the time of Duha. This immediately directed the minds towards the Duha prayer, and thus Anas (radi Allahu anhu) was asked about it.
Similarly, when the Messenger of Allah (sallallahu alayhi wa sallam) performed prayer at the house of ‘Itban bin Malik (radi Allahu anhu), ‘Itban (radi Allahu anhu) referred to this prayer as "Salat al-Duha."
This means that the Duha prayer was well-known among them.

(2)
Among the general public, there is a baseless notion that whoever starts performing the Duha prayer and then abandons it will become blind; therefore, people avoid performing it out of fear that, due to laziness, they might abandon it and thus become blind. In reality, this has no basis in fact.
This is a satanic ploy to deprive people of abundant good.
It is mentioned in the hadith that a human being has three hundred and sixty (360) joints, and it is necessary to give charity for each joint.
The Companions (radi Allahu anhum) asked:
"Who among us has the strength to give so much charity?" The Prophet (sallallahu alayhi wa sallam) replied:
"Burying the spittle found in the mosque or removing something harmful from the path is equal to charity for these joints.
If one is unable to do even this, then two units (rak‘ahs) of the Duha prayer are sufficient."
(Sahih Ibn Khuzaymah: 229/2)
Through such notions, Satan seeks to deprive people of the goodness and blessings of prayer.
We should not pay any attention to such things.
(Fath al-Bari: 75/3)