question #1 Sahih al-Bukhari 2636, Book 51, Hadith 68 : What is the ruling on buying back something that has been given in charity?

Once I gave a horse (for riding) in Allah’s Cause. Later I saw it being sold. I asked Allah’s Messenger (ﷺ)
(whether I could buy it). He said, “Don’t buy it, for you should not get back what you have given in
charity.”