question #3 Sahih al-Bukhari 7186, Book 93, Hadith 48 : What actions can be taken if a promise made by a Muslim is not feasible due to lack of resources?

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.