question #1 Sahih al-Bukhari 7186, Book 93, Hadith 48 : What is the significance of fulfilling promises in Islam, especially regarding the freeing of slaves?

The Prophet (ﷺ) came to know that one of his companions had given the promise of freeing his slave after
his death, but as he had no other property than that slave, the Prophet (ﷺ) sold that slave for 800 dirhams
and sent the price to him.