Bukhari

Hadith Commentary:
It is understood that this was the obligatory zakat, because it is that which is forbidden for the family of the Prophet (sallallahu alayhi wa sallam).
From this hadith, it is derived that it is necessary to teach religious matters to young children and to admonish them.

Hadith Commentary:
(1)
This heading consists of two parts:
➊ The payment of ‘ushr should be made at the time of harvesting the dates.
➋ Children should be kept away from prohibited actions.
Both aspects of the heading are established from this hadith: the noble Companions (radi Allahu anhum) would pay the ‘ushr as soon as they harvested the date crop.
In the Noble Qur’an, Muslims are directed towards this very matter. Allah the Exalted says:
﴿وَآتُوا حَقَّهُ يَوْمَ حَصَادِهِ﴾ (al-An‘am 6:141)
“And pay its due on the day of its harvest.”
The second aspect is established in that the Messenger of Allah (sallallahu alayhi wa sallam) forbade Hasan (radi Allahu anhu) from eating the dates of charity; rather, he took the date out of his mouth and threw it away. It is thus understood that even small children should be protected from the unlawful, and they should be taught that consuming the unlawful is a major sin, so that when they grow up, they will conscientiously avoid unlawful consumption.

(2)
A similar incident occurred with Husayn (radi Allahu anhu) as well. He relates that when he was young, he climbed up to the upper room, where there were some dates. He picked up a date and put it in his mouth, so the Messenger of Allah (sallallahu alayhi wa sallam) said:
“Throw it out, for charity is not lawful for us.”
(Musnad Ahmad: 1/201)