Allah's Messenger (ﷺ) has made Sadaqat-ul-Fitr obligatory, (and it was), either one Sa' of barley or one Sa' of dates (and its payment was obligatory) on young and old people, and on free men as well as on slaves.
Sahih al-Bukhari Book 24, Hadith 112
← Previous Hadith Ibn `Umar said, "The Prophet (ﷺ) made incumbent on every male or female, free man or slave, the payment of one Sa' of dates or barley as Sadaqat-ul-Fitr (or said Sadaqa-Ramadan)." The people then substituted half Sa' of wheat for that. Ibn `Umar used to give dates (as Sadaqat-ul-Fitr). Once there was scarcity of dates in Medina and Ibn `Umar gave barley. 'And Ibn `Umar used to give Sadaqat-ul- Fitr for every young and old person. He even used to give on behalf of my children. Ibn `Umar used to give Sadaqat-ul-Fitr to those who had been officially appointed for its collection. People used to give Sadaqat-ul-Fitr (even) a day or two before the `Id.

Sahih al-Bukhari Book 24, Hadith 111 Next Hadith → Al-Fadl (his brother) was riding behind Allah's Messenger (ﷺ) and a woman from the tribe of Khath'am came and Al-Fadl started looking at her and she started looking at him. The Prophet (ﷺ) turned Al-Fadl's face to the other side. The woman said, "O Allah's Messenger (ﷺ)! The obligation of Hajj enjoined by Allah on His devotees has become due on my father and he is old and weak, and he cannot sit firm on the Mount; may I perform Hajj on his behalf?" The Prophet (ﷺ) replied, "Yes, you may." That happened during the Hajj-al-Wida (of the Prophet (ﷺ) ).

Sahih al-Bukhari Book 25, Hadith 1